Step and repeat imprint lithography systems

ABSTRACT

Described are systems for patterning a substrate by imprint lithography. Imprint lithography systems include an imprint head configured to hold a template in a spaced relation to a substrate. The imprint lithography system is configured to dispense an activating light curable liquid onto a substrate or template. The system includes a light source that applies activating light to cure the activating light curable liquid.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] Embodiments presented herein relate to methods and systems forimprint lithography. More particularly, embodiments relate to methodsand systems for micro- and nano-imprint lithography processes.

[0003] 2. Description of the Relevant Art

[0004] Optical lithography techniques are currently used to make mostmicroelectronic devices. However, it is believed that these methods arereaching their limits in resolution. Sub-micron scale lithography hasbeen a critical process in the microelectronics industry. The use ofsub-micron scale lithography allows manufacturers to meet the increaseddemand for smaller and more densely packed electronic circuits on chips.It is expected that the microelectronics industry will pursue structuresthat are as small or smaller than about 50 nm. Further, there areemerging applications of nanometer scale lithography in the areas ofopto-electronics and magnetic storage. For example, photonic crystalsand high-density patterned magnetic memory of the order of terabytes persquare inch may require sub-100 nanometer scale lithography.

[0005] For making sub-50 nm structures, optical lithography techniquesmay require the use of very short wavelengths of light (e.g., about 13.2nm). At these short wavelengths, many common materials are not opticallytransparent and therefore imaging systems typically have to beconstructed using complicated reflective optics. Furthermore, obtaininga light source that has sufficient output intensity at these wavelengthsis difficult. Such systems lead to extremely complicated equipment andprocesses that may be prohibitively expensive. It is also believed thathigh-resolution e-beam lithography techniques, though very precise, aretoo slow for high-volume commercial applications.

[0006] Several imprint lithography techniques have been investigated aslow cost, high volume manufacturing alternatives to conventionalphotolithography for high-resolution patterning. Imprint lithographytechniques are similar in that they use a template containing topographyto replicate a surface relief in a film on the substrate. One form ofimprint lithography is known as hot embossing.

[0007] Hot embossing techniques face several challenges: i) pressuregreater than 10 MPa are typically required to imprint relief structures,ii) temperatures must be greater than the T_(g) of the polymer film,iii) patterns (in the substrate film) have been limited to isolationtrenches or dense features similar to repeated lines and spaces. Hotembossing is unsuited for printing isolated raised structures such aslines and dots. This is because the highly viscous liquids resultingfrom increasing the temperature of the substrate films require extremelyhigh pressures and long time durations to move the large volume ofliquids needed to create isolated structures. This pattern dependencymakes hot embossing unattractive. Also, high pressures and temperatures,thermal expansion, and material deformation generate severe technicalchallenges in the development of layer-to-layer alignment at theaccuracies needed for device fabrication.

SUMMARY OF THE INVENTION

[0008] In one embodiment, a patterned layer is formed by curing acurable liquid disposed on a substrate in the presence of a patternedtemplate. In an embodiment, a system for forming a patterned layer on asubstrate includes an imprint head and a motion stage. The imprint headis configured to hold a patterned template. The imprint head alsoincludes a fine orientation system. The fine orientation system allowsmotion of the patterned template with respect to a substrate to achievea substantially parallel orientation of the patterned template. In oneembodiment, the fine orientation system is a passive system that allowsthe template to self-correct for non-planarity when the templatecontacts a liquid disposed on the substrate. The imprint head furtherincludes a force detector. The force detector is coupled to the templateand is configured to determine a resistive force applied to the templateby the curable liquid disposed on the substrate. The substrate iscoupled to a motion stage. The motion stage is configured to support thesubstrate and to move the substrate in a plane substantially parallel tothe template. The imprint lithography system also includes a liquiddispenser. The liquid dispenser may be coupled to the imprint head or aportion of the system body. The liquid dispenser is configured todispense an activating light curable liquid onto the substrate. Theimprint lithography system also includes a light source opticallycoupled to the patterned template. The light source is configured todirect activating light through the patterned template and onto thecurable liquid during use.

[0009] Imprint lithography systems for forming features having a featuresize below 100 nm are typically sensitive to changes in temperature. Asthe temperature of the system increases, the supports (i.e., componentsthat support the template, substrate and other components of the imprintlithography system) may expand. Expansion of the supports may contributeto errors due to misalignment of the template with the substrate. In oneembodiment, supports are formed from a material that has a lowcoefficient of thermal expansion (e.g., less than about 20 ppm/° C.). Inaddition, the imprint lithography system may be placed in an enclosure.The enclosure is configured to inhibit temperature variations of greaterthan about 1° C. within the enclosure.

[0010] In an alternate embodiment, an imprint lithography systemincludes an imprint head, a motion stage, a liquid dispenser, a forcedetector and an activating light source. In this embodiment, a fineorientation system is coupled to the motion stage instead of the imprinthead. Thus, fine orientation is achieved by altering the orientation ofthe substrate until the portion of the substrate to be imprinted and thetemplate are substantially parallel. In this embodiment, imprint head iscoupled to a support in a fixed position, while motion stage isconfigured to move a substrate about an X-Y plane under the template.The other components of the imprint lithography system are substantiallythe same as described previously for other embodiments.

[0011] In another embodiment, an imprint lithography system includes animprint head, a motion stage, a substrate support, a liquid dispenser, aforce detector and an activating light source. The imprint head isconfigured to hold a patterned template. The imprint head also includesa fine orientation system. In one embodiment, the fine orientationsystem is a passive system that allows the template to self-correct fornon-planarity when the template contacts a liquid disposed on thesubstrate. The imprint head is coupled to a motion stage. The motionstage is configured to move the imprint head in a plane substantiallyparallel to the substrate. The substrate is coupled to a substratesupport. Substrate support is configured to hold the substrate in afixed position during use. The other components of the imprintlithography system are substantially the same as described previouslyfor other embodiments.

[0012] In another embodiment, an imprint lithography system includes animprint head, a motion stage, a substrate support, a liquid dispenser, aforce detector and an activating light source. The imprint head isconfigured to hold a patterned template. The imprint head is coupled toa motion stage. The motion stage is configured to move the imprint headin a plane substantially parallel to the substrate. The substrate iscoupled to a substrate support. Substrate support is configured to holdthe substrate in a fixed position during use. Substrate support alsoincludes a fine orientation system. The fine orientation system isconfigured to alter the orientation of the substrate until the portionof the substrate to be imprinted and the template are substantiallyparallel. The other components of the imprint lithography system aresubstantially the same as described previously for other embodiments.

[0013] In some embodiments, a patterned template may be designed toallow improved liquid control. When a template is brought into contactwith a liquid disposed on a substrate, the liquid will tend to expand tocover a larger area of the substrate than the liquid originally covered.In some processes it is advantageous that the liquid remains within anarea defined by the template. Proper design of a template will, in someembodiments, inhibit flow of liquid substantially beyond a perimeter ofthe template. A patterned template includes a first surface and aplurality of recesses formed in one or more patterning areas of thetemplate extending from the first surface toward an opposed secondsurface. The recesses define a plurality of features that are to beimprinted onto the substrate. The template also includes a border formedabout the perimeter of the patterning areas. The border is formed as arecess that extends from the first surface toward the second surface.The depth of the border is substantially greater than the depth of therecesses that define the features of the template. Patterned templatesthat include borders may be used in any of the herein described systems.

[0014] During use, the template is brought into contact with a curableliquid disposed on the surface of the substrate. The force applied tothe substrate by the template may cause the substrate to tilt,particularly when the template is positioned near an edge of thesubstrate. In one embodiment, the substrate is coupled to a substratesupport that includes a substrate tilt module. The substrate tilt moduleis configured to calibrate the tilt of the substrate surface during use.Additionally, the substrate tilt module is configured to inhibit tilt ofthe substrate due to compliance of the tilt module when pressure isexerted on the substrate. The substrate tilt module may be incorporatedinto either a motion stage that allows motion of the substrate duringuse or a fixed substrate support.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other objects and advantages of the invention will becomeapparent upon reading the following detailed description and uponreference to the accompanying drawings in which:

[0016]FIG. 1 depicts an embodiment of a system for imprint lithography;

[0017]FIG. 2 depicts an imprint lithography system enclosure;

[0018]FIG. 3 depicts an embodiment of an imprint lithography headcoupled to an imprint lithography system;

[0019]FIG. 4 depicts a projection view of an imprint head;

[0020]FIG. 5 depicts an exploded view of an imprint head;

[0021]FIG. 6 depicts a projection view of a first flexure member;

[0022]FIG. 7 depicts a projection view of a second flexure member;

[0023]FIG. 8 depicts a projection view of first and second flexuremembers coupled together;

[0024]FIG. 9 depicts a projection view of a fine orientation systemcoupled to a pre-calibration system of an imprint head;

[0025]FIG. 10 depicts a cross-sectional view of a pre-calibrationsystem;

[0026]FIG. 11 depicts a schematic diagram of a flexure system;

[0027]FIG. 12 depicts a projection view of a motion stage and an imprinthead of an imprint lithography system;

[0028]FIG. 13 depicts a schematic diagram of a liquid dispense system;

[0029]FIG. 14 depicts a projection view of an imprint head with a lightsource and camera optically coupled to the imprint head;

[0030]FIGS. 15 and 16 depict side views of an interface between a liquiddroplet and a portion of a template;

[0031]FIG. 17 depicts a cross-sectional view a first embodiment oftemplate configured for liquid confinement at the perimeter of thetemplate;

[0032]FIG. 18 depicts a cross-sectional view a second embodiment oftemplate configured for liquid confinement at the perimeter of thetemplate;

[0033] FIGS. 19 A-D depict cross-sectional views of a sequence of stepsof a template contacting a liquid disposed on a substrate.

[0034] FIGS. 20 A-B depict top and cross-sectional views, respectively,of a template having a plurality of patterning areas;

[0035]FIG. 21 depicts a projection view of a rigid template supportsystem coupled to a pre-calibration system of an imprint head;

[0036]FIG. 22 depicts an imprint head coupled to an X-Y motion system;

[0037] FIGS. 23A-23F depict cross-sectional views of a negative imprintlithography process;

[0038] FIGS. 24A-24D depict cross-sectional views of a negative imprintlithography process with a transfer layer;

[0039] FIGS. 25A-25D depict cross-sectional views of a positive imprintlithography process;

[0040] FIGS. 26A-26C depict cross-sectional views of a positive imprintlithography process with a transfer layer;

[0041] FIGS. 27A-27E depict cross-sectional views of a combined positiveand negative imprint lithography process;

[0042]FIG. 28 depicts a schematic of an optical alignment measuringdevice positioned over a template and substrate;

[0043]FIG. 29 depicts a scheme for determining the alignment of atemplate with respect to a substrate using alignment marks bysequentially viewing and refocusing;

[0044]FIG. 30 depicts a scheme for determining the alignment of atemplate with respect to a substrate using alignment marks and polarizedfilters;

[0045]FIG. 31 depicts a top view of an alignment mark that is formedfrom polarizing lines;

[0046] FIGS. 32A-32C depict top views of patterns of curable liquidapplied to a substrate;

[0047] FIGS. 33A-33C depict a scheme for removing a template from asubstrate after curing;

[0048]FIG. 34 depicts an embodiment of a template positioned over asubstrate for electric field based lithography;

[0049] FIGS. 35A-35D depict a first embodiment of a process for formingnanoscale structures using contact with a template;

[0050] FIGS. 36A-36C depict a first embodiment of a process for formingnanoscale structures without contacting a template;

[0051] FIGS. 37A-37C depict a template that includes a continuouspatterned conductive layer disposed on a non-conductive base;

[0052]FIG. 38 depicts a schematic, partial cross-sectional view of anembodiment of an electrically addressable template;

[0053]FIG. 39 depicts a motion stage having a substrate tilt module;

[0054]FIG. 40 depicts a schematic drawing of a substrate support;

[0055]FIG. 41 depicts a schematic drawing of an imprint lithographysystem that includes an imprint head disposed below a substrate support;and

[0056]FIG. 42 depicts a motion stage that includes a fine orientationsystem.

[0057] While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawing and will herein be described in detail. It shouldbe understood, however, that the drawings and detailed descriptionthereto are not intended to limit the invention to the particular formdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0058] Embodiments presented herein generally relate to systems,devices, and related processes of manufacturing small devices. Morespecifically, embodiments presented herein relate to systems, devices,and related processes of imprint lithography. For example, theseembodiments may be used for imprinting sub 100 features on a substrate,such as a semiconductor wafer. It should be understood that theseembodiments may also be used to manufacture other kinds of devicesincluding, but not limited to: patterned magnetic media for datastorage, micro-optical devices, micro-electro-mechanical system,biological testing devices, chemical testing and reaction devices, andX-ray optical devices.

[0059] Imprint lithography processes have demonstrated the ability toreplicate high-resolution (sub-50 nm) images on substrates usingtemplates that contain images as topography on their surfaces. Imprintlithography may be used in patterning substrates in the manufacture ofmicroelectronic devices, optical devices, MEMS, opto-electronics,patterned magnetic media for storage applications, etc. Imprintlithography techniques may be superior to optical lithography for makingthree-dimensional structures such as micro lenses and T-gate structures.Components of an imprint lithography system, including the template,substrate, liquid and any other materials that may affect the physicalproperties of the system, including but not limited to surface energy,interfacial energies, Hamacker constants, Van der Waals'0 forces,viscosity, density, opacity, etc., are engineered to properlyaccommodate a repeatable process.

[0060] Methods and systems for imprint lithography are discussed in U.S.Pat. No. 6,334,960 to Willson et al. entitled “Step and Flash ImprintLithography” which is incorporated herein by reference. Additionalmethods and systems for imprint lithography are further discussed inU.S. Patent Applications: U.S. Ser. No. 09/908,455 filed Jul. 17, 2001,entitled “Method and System of Automatic Fluid Dispensing for ImprintLithography Processes”; U.S. Ser. No. 09/907,512 filed Jul. 16, 2001entitled “High-Resolution Overlay Alignment Methods and Systems forImprint Lithography”; U.S. Ser. No. 09/920,341 filed Aug. 1, 2001entitled “Methods for High-Precision Gap Orientation Sensing Between aTransparent Template and Substrate for Imprint Lithography”; U.S. Ser.No. 09/934,248 filed Aug. 21, 2001 entitled “Flexure Based Macro MotionTranslation Stage”; U.S. Ser. No. 09/698,317 filed Oct. 27, 2000entitled “High-Precision Orientation Alignment and Gap Control Stagesfor Imprint Lithography Processes”; U.S. Ser. No. 09/976,681 filed Oct.12, 2001 entitled “Template Design for Room Temperature, Low PressureMicro- and Nano-Imprint Lithography”; U.S. Ser. No. 10/136,188 filed May1, 2002 entitled “Methods of Manufacturing a Lithography Template” toVoison; and U.S. patent application entitled “Method and System forFabricating Nanoscale Patterns in Light Curable Compositions Using anElectric Field to Willson, et al. filed May 16, 2001 all of which areincorporated herein by reference. Further methods and systems arediscussed in the following publications, all of which are incorporatedherein by reference, “Design of Orientation Stages for Step and FlashImprint Lithography,” B. J. Choi, S. Johnson, M. Colburn, S. V.Sreenivasan, C. G. Willson, To appear in J. of Precision Engineering;“Large area high density quantized magnetic disks fabricated usingnanoimprint lithography,” W. Wu, B. Cui, X. Y. Sun, W. Zhang, L. Zhunag,and S. Y. Chou., J. Vac Sci Technol B 16 (6) 3825-3829 November-December1998; “Lithographically-induced Self-assembly of Periodic PolymerMicropillar Arrays,” S. Y. Chou, L. Zhuang, J Vac Sci Tech B 17 (6),3197-3202, 1999 and “Large Area Domain Alignment in Block Copolymer ThinFilms Using Electric Fields,” P. Mansky, J. DeRouchey, J. Mays, M.Pitsikalis, T. Morkved, H. Jaeger and T. Russell, Macromolecules 13,4399 (1998).

System for Imprint Lithography

[0061] Overall System Description

[0062]FIG. 1 depicts an embodiment of a system for imprint lithography3900. System 3900 includes an imprint head 3100. Imprint head 3100 ismounted to an imprint head support 3910. Imprint head 3100 is configuredto hold a patterned template 3700. Patterned template 3700 includes aplurality of recesses that define a pattern of features to be imprintedinto a substrate. Imprint head 3100 or motion stage 3600 is furtherconfigured to move patterned template 3700 toward and away from asubstrate to be imprinted during use. System 3900 also includes a motionstage 3600. Motion stage 3600 is mounted to motion stage support 3920.Motion stage 3600 is configured to hold a substrate and move thesubstrate in a generally planar motion about motion stage support 3920.System 3900 further includes a curing light system 3500 coupled toimprint head 3100. Activating light system 3500 is configured to producea curing light and direct the produced curing light through patternedtemplate 3700 coupled to imprint head 3100. Curing light includes lightat an appropriate wavelength to cure a polymerizable liquid. Curinglight includes ultraviolet light, visible light, infrared light, x-rayradiation and electron beam radiation.

[0063] Imprint head support 3910 is coupled to motion stage support 3920by bridging supports 3930. In this manner imprint head 3100 ispositioned above motion stage 3600. Imprint head support 3910, motionstage support 3920 and bridging supports 3930 are herein collectivelyreferred to as the system “body.” The components of the system body maybe formed from thermally stable materials. Thermally stable materialshave a thermal expansion coefficient of less than about 10 ppm deg. C.at about room temperature (e.g. 25 deg C.). In some embodiments, thematerial of construction may have a thermal expansion coefficient ofless than about 10 ppm deg. C., or less than 1 ppm deg. C. Examples ofsuch materials include silicon carbide, certain alloys of iron,including but not limited to: certain alloys of steel and nickel (e.g.,alloys commercially available under the name INVAR®), and certain alloysof steel, nickel and cobalt (e.g., alloys commercially available underthe name SUPER INVAR™). Additional examples of such materials includecertain ceramics, including but not limited to: ZERODUR® ceramic. Motionstage support 3920 and bridging supports 3930 are coupled to a supporttable 3940. Support table 3940 provides a substantially vibration freesupport for the components of system 3900. Support table 3940 isolatessystem 3900 from ambient vibrations (e.g., due to works, othermachinery, etc.). Motion stages and vibration isolation support tablesare commercially available from Newport Corporation of Irvine, Calif.

[0064] As used herein, the “X-axis” refers to the axis that runs betweenbridging supports 3930. As used herein the “Y-axis” refers to the axisthat is orthogonal to the X-axis. As used herein the “X-Y plane” is aplane defined by the X-axis and the Y-axis. As used herein the “Z-axis”refers to an axis running from motion stage support 3920 to imprint headsupport 3910, orthogonal to the X-Y plane. Generally an imprint processinvolves moving the substrate, or the imprint head, along an X-Y planeuntil the proper position of the substrate with respect to the patternedtemplate is achieved. Movement of the template, or motion stage, alongthe Z-axis, will bring the patterned template to a position that allowscontact between the patterned template and a liquid disposed on asurface of the substrate.

[0065] System 3900 may be placed in an enclosure 3960, as depicted inFIG. 2. Enclosure 3960 encompasses imprint lithography system 3900 andprovides a thermal and air barrier to the lithography components.Enclosure 3960 includes a movable access panel 3962 that allows accessto the imprint head and motion stage when moved to an “open” position,as depicted in FIG. 2. When in a “closed” position, the components ofsystem 3900 are at least partially isolated from the room atmosphere.Access panel 3962 also serves as a thermal barrier to reduce the effectsof temperature changes within the room on the temperature of thecomponents within enclosure 3960. Enclosure 3960 includes a temperaturecontrol system. A temperature control system is used to control thetemperature of components with enclosure 3960. In one embodiment,temperature control system is configured to inhibit temperaturevariations of greater than about 1° C. within enclosure 3960. In someembodiments, a temperature control system inhibits variations of greaterthan about 0.1° C. In one embodiment, thermostats or other temperaturemeasuring devices in combination with one or more fans may be used tomaintain a substantially constant temperature with enclosure 3960.

[0066] Various user interfaces may also be present on enclosure 3960. Acomputer controlled user interface 3964 may be coupled to enclosure3960. User interface 3964 may depict the operating parameters,diagnostic information, job progress and other information related tothe functioning of the enclosed imprint system 3900. User interface 3964may also be configured to receive operator commands to alter theoperating parameters of system 3900. A staging support 3966 may also becoupled to enclosure 3960. Staging support 3966 is used by an operatorto support substrates, templates and other equipment during an imprintlithography process. In some embodiments, staging support 3966 mayinclude one or more indentations 3967 configured to hold a substrate(e.g., a circular indentation for a semiconductor wafer). Stagingsupport 3966 may also include one or more indentations 3968 for holdinga template.

[0067] Additional components may be present depending on the processesthat the imprint lithography system is designed to implement. Forexample, for semiconductor processing equipment including, but notlimited to, an automatic wafer loader, an automatic template loader andan interface to a cassette loader (all not shown) may be coupled toimprint lithography system 3900.

[0068] Imprint Head

[0069]FIG. 3 depicts an embodiment of a portion of an imprint head 3100.Imprint head 3100 includes a pre-calibration system 3109 and a fineorientation system 3111 coupled to the pre-calibration system. Templatesupport 3130 is coupled to fine orientation system 3111. Templatesupport 3130 is designed to support and couple a template 3700 to fineorientation system 3111.

[0070] Referring to FIG. 4, a disk-shaped flexure ring 3124, which makesup a portion of the pre-calibration system 3109 is coupled to imprinthead housing 3120. Imprint head housing 3120 is coupled to a middleframe 3114 with guide shafts 3112 a, 3112 b. In one embodiment, three(3) guide shafts may be used (the back guide shaft is not visible inFIG. 4) to provide a support for housing 3120. Sliders 3116 a and 3116 bcoupled to corresponding guide shafts 3112 a, 3112 b about middle frame3114 are used to facilitate the up and down motion of housing 3120. Adisk-shaped base plate 3122 is coupled to the bottom portion of housing3120. Base plate 3122 may be coupled to flexure ring 3124. Flexure ring3124 supports the fine orientation system components that include firstflexure member 3126 and second flexure member 3128. The operation andconfiguration of the flexure members 3126, 3128 are discussed in detailbelow.

[0071]FIG. 5 depicts an exploded view of imprint head 3700. As shown inFIG. 5, actuators 3134 a, 3134 b, 3134 c are fixed within housing 3120and coupled to base plate 3122 and flexure ring 3124. In operation,motion of actuators 3134 a, 3134 b, and 3134 c controls the movement offlexure ring 3124. Motion of actuators 3134 a, 3134 b, and 3134 c mayallow for a coarse pre-calibration. In some embodiments, actuators 3134a, 3134 b, and 3134 c may be equally spaced around housing 3120.Actuators 3134 a, 3134 b, 3134 c and flexure ring 3124 together form thepre-calibration system. Actuators 3134 a, 3134 b, 3134 c allowtranslation of flexure ring 3124 along the Z-axis to control the gapaccurately.

[0072] Imprint head 3100 also include a mechanism that enables fineorientation control of template 3700 so that proper orientationalignment may be achieved and a uniform gap may be maintained by thetemplate with respect to a substrate surface. Alignment and gap controlis achieved, in one embodiment, by the use of first and second flexuremembers, 3126 and 3128, respectively.

[0073]FIGS. 6 and 7 depicted embodiments of first and second flexuremembers, 3126 and 3128, respectively, in more detail. As depicted inFIG. 6, first flexure member 3126 includes a plurality of flexure joints3160 coupled to corresponding rigid bodies 3164 and 3166. Flexure joints3160 may be notch shaped to provide motion of rigid bodies 3164 and 3166about pivot axes that are located along the thinnest cross section ofthe flexure joints. Flexure joints 3160 and rigid body 3164 togetherform arm 3172, while additional flexure joints 3160 and rigid body 3166together form arm 3174. Arms 3172 and 3174 are coupled to and extendfrom first flexure frame 3170. First flexure frame 3170 has an opening3182, which allows curing light (e.g., ultraviolet light) to passthrough first flexure member 3126. In the depicted embodiment, fourflexure joints 3160 allow motion of first flexure frame 3170 about afirst orientation axis 3180. It should be understood, however, that moreor less flexure joints may be used to achieve the desired control. Firstflexure member 3126 is coupled to second flexure member 3128 throughfist flexure frame 3170, as depicted in FIG. 8. First flexure member3126 also includes two coupling members 3184 and 3186. Coupling members3184 and 3186 include openings that allow attachment of the couplingmembers to flexure ring 3124 using any suitable fastening means.Coupling members 3184 and 3186 are coupled to first flexure frame 3170via arms 3172 and 3174 as depicted.

[0074] Second flexure member 3128 includes a pair of arms 3202 and 3204extending from second flexure frame 3206, as depicted in FIG. 7. Flexurejoints 3162 and rigid body 3208 together form arm 3202, while additionalflexure joints 3162 and rigid body 3210 together form arm 3204. Flexurejoints 3162 may be notch shaped to provide motion of rigid bodies 3210and 3204 about pivot axes that are located along the thinnest crosssection of the flexure joints. Arms 3202 and 3204 are coupled to andextend from template support 3130. Template support 3130 is configuredto hold and retain at least a portion of a patterned template. Templatesupport 3130 also has an opening 3212, which allows curing light (e.g.,ultraviolet light) to pass through second flexure member 3128. In thedepicted embodiment, four flexure joints 3162 allow motion of templatesupport 3130 about a second orientation axis 3200. It should beunderstood, however, that more or less flexure joints may be used toachieve the desired control. Second flexure member 3128 also includesbraces 3220 and 3222. Braces 3220 and 3222 include openings that allowattachment of the braces to portions of first flexure member 3126.

[0075] In one embodiment, first flexure member 3126 and second flexuremember 3128 are joined as shown in FIG. 8 to form fine orientationsection 3111. Braces 3220 and 3222 are coupled to first flexure frame3170 such that the first orientation axis 3180 of first flexure member3126 and second orientation axis 3200 of second flexure member aresubstantially orthogonal to each other. In such a configuration, firstorientation axis 3180 and second orientation axis 3200 intersect at apivot point 3252 at approximately the center region of a patternedtemplate 3700 disposed in template support 3130. This coupling of thefirst and second flexure member allows fine alignment and gap control ofpatterned template 3700 during use. While the first and second flexuremembers are depicted as discrete elements, it should be understood thatthe first and second flexure member may be formed from a single machinedpart where the flexure members are integrated together. Flexure members3126 and 3128 are coupled by mating of surfaces such that motion ofpatterned template 3700 occurs about pivot point 3252, substantiallyreducing “swinging” and other motions that may shear imprinted featuresfollowing imprint lithography. Fine orientation section impartsnegligible lateral motion at the template surface and negligibletwisting motion about the normal to the template surface due toselectively constrained high structural stiffness of the flexure joints.Another advantage of using the herein described flexure members is thatthey do not generate substantial amounts of particles, especially whencompared with frictional joints. This is offers an advantage for imprintlithography processes, as particles may be disrupt such processes.

[0076]FIG. 9 depicts the assembled fine orientation system coupled tothe pre-calibration system. Patterned template 3700 is positioned withintemplate support 3130 that is part of second flexure member 3128. Secondflexure member 3128 is coupled to first flexure member 3126 in asubstantially orthogonal orientation. First flexure member 3124 iscoupled to flexure ring 3124 via coupling members 3186 and 3184. Flexurering 3124 is coupled to base plate 3122, as has been described above.

[0077]FIG. 10 represents a cross-section of the pre-calibration systemlooking through cross-section 3260. As shown in FIG. 10, flexure ring3124 is coupled to base plate 3122 with actuator 3134. Actuator 3134includes an end 3270 coupled to a force detector 3135 that contactsflexure ring 3124. During use activation of actuator 3134 causesmovement of end 3270 toward or away from flexure ring 3124. The movementof end 3270 toward flexure ring 3124 induces a deformation of theflexure ring and causes translation of the fine orientation system alongthe Z-axis toward the substrate. Movement of base 3270 away from flexurering allows the flexure ring to move to its original shape and, in theprocess, moves the fine orientation stage away from the substrate.

[0078] In a typical imprint process the template is disposed in atemplate holder coupled to the fine orientation system, as depicted inprevious figures. The template is brought into contact with a liquid ona surface of a substrate. Compression of the liquid on the substrate asthe template is brought closer to the substrate causes a resistive forceto be applied by the liquid onto the template. This resistive force istranslated through the fine orientation system and to flexure ring 3124as shown in both FIGS. 9 and 10. The force applied against flexure ring3124 will also be translated as a resistive force to actuators 3134. Theresistive force applied to an actuator 3134 may be determined usingforce sensor 3135. Force sensor 3135 may be coupled to actuator 3134such that a resistive force applied to actuator 3135 during use may bedetermined and controlled.

[0079]FIG. 11 depicts a flexure model, denoted generally as 3300, usefulin understanding the principles of operation of a fine decoupledorientation stage, such as the fine orientation section describedherein. Flexure model 3300 may include four parallel joints: Joints 1,2, 3 and 4, that provide a four-bar-linkage system in its nominal androtated configurations. Line 3310 denotes an axis of alignment of Joints1 and 2. Line 3312 denotes an axis of alignment of Joints 3 and 4. Angleα₁ represents an angle between a perpendicular axis through the centerof template 3700 and line 3310. Angles α₂ represents a perpendicularaxis through the center of template 3700 and line 3310. Angles α₁ andα₂, in some embodiments, are selected so that the compliant alignmentaxis (or orientation axis) lies substantially at the surface of template3700. For fine orientation changes, rigid body 3314 between Joints 2 and3 may rotate about an axis depicted by Point C. Rigid body 3314 may berepresentative of template support 3130 of second flexure member 3128.

[0080] Fine orientation system generates pure tilting motions with nosubstantial lateral motions at the surface of a template coupled to thefine orientation system. The use of flexure arms may provide fineorientation system with high stiffness in the directions where sidemotions or rotations are undesirable and lower stiffness in directionswhere necessary orientation motions are desirable. Fine orientationsystem, therefore allows rotations of the template support, andtherefore the template, about the pivot point at the surface oftemplate, while providing sufficient resistance in a directionperpendicular to the template and parallel to the template to maintainthe proper position with respect to the substrate. In this manner apassive orientation system is used for orientation of the template to aparallel orientation with respect to a template. The term “passive”refers to a motion that occurs without any user or programmablecontroller intervention, i.e., the system self-corrects to a properorientation by contact of the template with the liquid. Alternateembodiments in which the motion of the flexure arms is controlled bymotors to produce an active flexure may also be implemented.

[0081] Motion of the fine orientation stage may be activated by director indirect contact with the liquid. If the fine orientation stage ispassive, then it is, in one embodiment, designed to have the mostdominant compliance about two orientation axes. The two orientation axeslie orthogonal to each other and lie on the imprinting surface of animprinting member disposed on the fine orientation stage. The twoorthogonal torsional compliance values are set to be the same for asymmetrical imprinting member. A passive fine orientation stage isdesigned to alter the orientation of the template when the template isnot parallel with respect to a substrate. When the template makescontact with liquid on the substrate, the flexure members compensate forthe resulting uneven liquid pressure on the template. Such compensationmay be affected with minimal or no overshoot. Further, a fineorientation stage as described above may hold the substantially parallelorientation between the template and substrate for a sufficiently longperiod to allow curing of the liquid.

[0082] Imprint head 3100 is mounted to imprint head support 3910 asdepicted in FIG. 1. In this embodiment, imprint head 3910 is mountedsuch that the imprint head remains in a fixed position at all times.During use, all movement along the X-Y plane is performed to thesubstrate by motion stage 3600.

[0083] Motion Stage

[0084] Motion stage 3600 is used to support a substrate to be imprintedand move the substrate along an X-Y plane during use. Motion stage, insome embodiments, is capable of moving a substrate over distances of upto several hundred millimeters with an accuracy of at least±30 nm,preferably with an accuracy of about±10 nm. In one embodiment, motionstage includes a substrate chuck 3610 that is coupled to carriage 3620,as depicted in FIG. 12. Carriage 3620 is moved about a base3630 on africtional bearing system or a non-frictional bearing system. In oneembodiment, a non-frictional bearing system that includes an air bearingis used. Carriage 3620 is suspended above base 3630 of motion stageusing, in one embodiment, an air layer (i.e., the “air bearing”).Magnetic or vacuum systems may be used to provide a counter balancingforce to the air bearing level. Both magnetic based and vacuum basedsystems are commercially available from a variety of suppliers and anysuch systems may be used in an imprint lithography process. One exampleof a motion stage that is applicable to imprint lithography processes isthe Dynam YX motion stage commercially available from NewportCorporation, Irvine Calif. The motion stage also may include a tip tiltstage similar to the calibration stage, designed to approximately levelthe substrate to the X Y motion plane. It also may include one or moretheta stages to orient the patterns on the substrate to the X Y motionaxes.

[0085] Liquid Dispenser

[0086] System 3900 also includes a liquid dispense system which is usedto dispense a curable liquid onto a substrate. Liquid dispense system iscoupled to the system body. In one embodiment, a liquid dispense systemis coupled to imprint head 3100. FIG. 3 depicts liquid dispenser head2507 of a liquid dispense system extending out from cover 3127 ofimprint head 3100. Various components of liquid dispense system 3125 maybe disposed in cover 3127 of imprint head 3100.

[0087] A schematic of a liquid dispense system is depicted in FIG. 13.In an embodiment, a liquid dispense system includes a liquid container2501. Liquid container 2501 is configured to hold an activating lightcurable liquid. Liquid container 2501 is coupled to a pump 2504 viainlet conduit 2502. An inlet valve 2503 is positioned between liquidcontainer 2501 and pump 2504 to control flow of through inlet conduit2502. Pump 2504 is coupled to a liquid dispenser head 2507 via outletconduit 2506.

[0088] Liquid dispense system is configured to allow precise volumecontrol of the amount of liquid dispensed onto an underlying substrate.In one embodiment, liquid control is achieved using a piezoelectricvalve as pump 2504. Piezoelectric valves are available commerciallyavailable from the Lee Company, Westbrook, Conn. During use, a curableliquid is drawn into pump 2504 through inlet conduit 2502. When asubstrate is properly positioned below, pump 2504 is activated to forcea predetermined volume of liquid through outlet conduit 2506. The liquidis then dispensed through liquid dispenser head 2507 onto the substrate.In this embodiment, liquid volume control is achieved by control of pump2504. Rapid switching of the pump from an open to closed state allows acontrolled amount of liquid to be sent to dispenser head 2507. Pump 2504is configured to dispense liquid in volumes of less than about 1μL. Theoperation of pump 2504 may allow either droplets of liquid or acontinuous pattern of liquid to be dispensed onto the substrate.Droplets of liquid are applied by rapidly cycling the pump from an opento closed state. A stream of liquid is produced on the substrate byleaving the pump in an open state and moving the substrate under theliquid dispenser head.

[0089] In another embodiment, liquid volume control may be achieved byuse of liquid dispenser head 2507. In such a system, pump 2504 is usedto supply a curable liquid to liquid dispenser head 2507. Small drops ofliquid whose volume may be accurately specified are dispensed using aliquid dispensing actuator. Examples of liquid dispensing actuatorsinclude micro-solenoid valves or piezo-actuated dispensers.Piezo-actuated dispensers are commercially available from MicroFabTechnologies, Inc., Plano, Tex. Liquid dispensing actuators areincorporated into liquid dispenser head to allow control of liquiddispensing. Liquid dispensing actuators are configured to dispensebetween about 50 pL to about 1000 pL of liquid per drop of liquiddispensed. Advantages of a system with a liquid dispensing actuatorinclude faster dispensing time and more accurate volume control. Liquiddispensing systems are further described in U.S. Ser. No. 09/908,455filed Jul. 17, 2001, entitled “Method and System of Automatic FluidDispensing for Imprint Lithography Processes” which is incorporatedherein by reference.

[0090] Coarse Measurement System

[0091] Coarse determination of the position of the template and thesubstrate is determined by the use of linear encoders (e.g., exposedlinear encoders). Encoders offer a coarse measurement on the order of0.01μm. Linear encoders include a scale coupled to the moving object anda reader coupled to the body. The scale may be formed from a variety ofmaterials including glass, glass ceramics, and steel. The scale includesa number of markings that are read by the reader to determine a relativeor absolute position of the moving object. The scale is coupled to themotion stage by means that are known in the art. A reader is coupled tothe body and optically coupled to the scale. In one embodiment, anexposed linear encoder may be used. Encoders may be configured todetermine the position of the motion stage along either a single axis,or in a two-axis plane. An example of an exposed two-axis linear encoderis the PP model encoder available from Heidenhain Corporation,Schaumburg, Illinois. Generally, encoders are built into manycommercially available X-Y motion stages. For example, the Dynam YXmotion stage available from Newport Corp has a two-axis encoder builtinto the system.

[0092] The coarse position of the template along the Z-axis is alsodetermined using a linear encoder. In one embodiment, an exposed linearencoder may be used to measure the position of the template. A scale ofthe linear encoder, in one embodiment, is coupled to the pre-calibrationring of the imprint head. Alternatively, the scale may be coupleddirectly to the template support 3130. The reader is coupled to the bodyand optically coupled to the scale. Position of the template isdetermined along the Z-axis by use of encoders.

[0093] Air Gauges

[0094] In an embodiment, an air gauge 3135 may be coupled to imprinthead 3100, as depicted in FIG. 3. Air gauge 3135 is used to determinewhether a substrate disposed on a motion stage is substantially parallelto a reference plane. As used herein, an “air gauge” refers to a devicethat measures the pressure of a stream of air directed toward a surface.When a substrate is disposed under an outlet of air gauge 3135, thedistance the substrate is from the outlet of air gauge 3135 willinfluence the pressure the air gauge senses. Generally, the further awayfrom the air gauge the substrate is, the lesser the pressure.

[0095] In such a configuration, air gauge 3135 may be used to determinedifferences in pressure resulting from changes in the distance betweenthe substrate surface and the air gauge. By moving air gauge 3135 alongthe surface of the substrate, the air gauge determines the distancebetween the air gauge and the substrate surface at the various pointsmeasured. The degree of planarity of the substrate with respect to theair gauge is determined by comparing the distance between the air gaugeand substrate at the various points measured. The distance between atleast three points on the substrate and the air gauge is used todetermine if a substrate is planar. If the distance is substantially thesame, the substrate is considered to be planar. Significant differencesin the distances measured between the substrate and the air gaugeindicates a non-planar relationship between the substrate and the airgauge. This non-planar relationship may be caused by the non-planarityof the substrate or a tilt of the substrate. Prior to use, a tilt of thesubstrate is corrected to establish a planar relationship between thesubstrate and the template. template using the tip tilt stage attachedto the X Y stage. Suitable air gauges may be obtained from Senex Inc.

[0096] During use of air gauges, the substrate or template is placedwithin the measuring range of the air gauge. Motion of the substratetoward the air gauge may be accomplished by either Z-axis motion of theimprint head or Z-axis motion of the motion stage.

[0097] Light Source

[0098] In an imprint lithography process, a light curable liquid isdisposed on a surface of the substrate. A patterned template is broughtinto contact with the light curable liquid and activating light isapplied to the light curable liquid. As used herein “activating light”means light that may affect a chemical change. Activating light mayinclude ultraviolet light (e.g., light having a wavelength between about200 nm to about 400 nm), actinic light, visible light or infrared light.Generally, any wavelength of light capable of affecting a chemicalchange may be classified as activating. Chemical changes may bemanifested in a number of forms. A chemical change may include, but isnot limited to, any chemical reaction that causes a polymerization or across-linking reaction to take place. The activating light, in oneembodiment, is passed through the template prior to reaching thecomposition. In this manner the light curable liquid is cured to formstructures complementary to the structures formed on the template.

[0099] In some embodiment, activating light source 3500 is anultraviolet light source capable of producing light having a wavelengthbetween about 200 nm to about 400 nm. Activating light source 3500 isoptically coupled to the template as depicted in FIG. 1. In oneembodiment, activating light source 3500 is positioned proximate toimprint head 3100. Imprint head 3100 includes a mirror 3121 (depicted inFIG. 4, which reflects light from the activating light source to thepatterned template. Light passes through an opening in the body ofimprint head 3100 and is reflected by mirror 3121 toward 3700. In thismanner, activating light source irradiates a patterned template withoutbeing disposed in imprint head 3100.

[0100] Most activating light sources produce a significant amount ofheat during use. If activating light source 3500 is too close to imprintsystem 3500, heat from the light source will radiate toward the body ofthe imprint system and may cause the temperature of portions of the bodyto increase. Since many metals expand when heated, the increase intemperature of a portion of the body of the imprint system may cause anexpansion of the body to expand. This expansion may affect the accuracyof the imprint system when sub-100 features are being produced.

[0101] In one embodiment, activating light source is positioned at asufficient distance from the body such that system body is insulatedfrom heat produced by activating light source 3500 by the interveningair between activating light source 3500 and imprint head 3100. FIG. 14depicts an activating light source 3500 optically coupled to imprinthead 3100. Activating light source 3500 includes an optical system 3510that projects light generated by a light source toward imprint head3100. Light passes from optical system 3510 into imprint head 3100 viaopening 3123. Light is then reflected toward a template coupled toimprint head 3110 by mirror 3121 disposed within the imprint head (seeFIG. 4). In this manner, the light source is thermally insulated fromthe body. A suitable light source may be obtained from OAI Inc, SantaClara Calif.

[0102] Optical Alignment Devices

[0103] One or more optical measuring devices may be coupled to imprinthead 3910 and/or motion stage 3920. Generally, an optical measuringdevice is any device that allows the position and/or orientation of atemplate with respect to a substrate to be determined.

[0104] Turning to FIG. 14, a through the template optical imaging system3800 is optically coupled to the imprint head. Optical imaging system3800 includes an optical imaging device 3810 and an optical system 3820.Optical imaging device 3810, in one embodiment, is a CCD microscope.Optical imaging system 3800 is optically coupled to the template throughimprint head. Optical imaging system 3800 is also optically coupled to asubstrate, when the substrate is disposed under the patterned template.Optical imaging system 3800 is used to determine the placement errorbetween a patterned template and an underlying substrate as describedherein. In one embodiment, mirror 3121 (depicted in FIG. 4) is movablewithin the imprint head. During an alignment or optical inspectionprocess, mirror 3121 is moved out of the optical path of the opticalimaging system.

[0105] During use of an optical alignment device, the substrate ortemplate is placed within the measuring range (e.g., the filed of view)of the air optical imaging system. Motion of the substrate toward theoptical imagining system may be accomplished by either Z-axis motion ofthe imprint head or Z-axis motion of the motion stage.

[0106] Light Curable Liquid

[0107] As previously mentioned, a light curable liquid is placed on asubstrate and a template is brought into contact with the liquid duringan imprint lithography process. The curable liquid is a low viscosityliquid monomer solution. A suitable solution may have a viscosityranging from about 0.01 cps to about 100 cps (measured at 25° C.). Lowviscosities are especially desirable for high-resolution (e.g., sub-100) structures. Low viscosities also lead to faster gap closing.Additionally, low viscosities result in faster liquid filling of the gaparea at low pressures. In particular, in the sub-50 nm regime, theviscosity of the solution should be at or below about 30 cps, or morepreferably below about 5 cps (measured at 25° C.).

[0108] Many of the problems encountered with other lithographytechniques may be solved by using a low viscosity light curable liquidin an imprint lithography process. Patterning of low viscosity lightcurable liquids solves each of the issues facing hot embossingtechniques by utilizing a low-viscosity, light-sensitive liquid. Alsouse of a thick, rigid, transparent template offers the potential foreasier layer-to-layer alignment. The rigid template is, in general,transparent to both liquid activating light and alignment markmeasurement light.

[0109] The curable liquid may be composed of a variety of polymerizablematerials. Generally, any photopolymerizable material may be used.Photopolymerizable materials may include a mixture of monomers and aphotoinitiator. In some embodiments, the curable liquid may include oneor more commercially available negative photoresist materials. Theviscosity of the photoresist material may be reduced by diluting theliquid photoresist with a suitable solvent.

[0110] In an embodiment, a suitable curable liquid includes a monomer, asilylated monomer, and an initiator. A crosslinking agent and a dimethylsiloxane derivative may also be included. Monomers include, but are notlimited to, acrylate and methacylate monomers. Examples of monomersinclude, but are not limited to, butyl acrylate, methyl acrylate, methylmethacrylate, or mixtures thereof. The monomer makes up approximately 25to 50% by weight of the curable liquid. It is believed that the monomerensures adequate solubility of the photoinitiator in the curable liquid.It is further believed that the monomer provides adhesion to anunderlying organic transfer layer, when used.

[0111] The curable liquid may also include a silylated monomer.Silylated monomers in general are polymerizable compounds that include asilicon group. Classes of silylated monomers include, but are notlimited to, silane acrylyl and silane methacrylyl derivatives. Specificexamples include methacryloxypropyl tris(tri-methylsiloxy)silane and(3-acryloxypropyl)tris(tri-methoxysiloxy)-silane. Silylated monomers maybe present in amounts from 25 to 50% by weight. The curable liquid mayalso include a dimethyl siloxane derivative. Examples of dimethylsiloxane derivatives include, but are not limited to, (acryloxypropyl)methylsiloxane dimethylsiloxane copolymer, acryloxypropyl methylsiloxanehomopolymer, and acryloxy terminated polydimethylsiloxane. Dimethylsiloxane derivatives are present in amounts from about 0 to 50% byweight. It is believed that the silylated monomers and the dimethylsiloxane derivatives may impart a high oxygen etch resistance to thecured liquid. Additionally, both the silylated monomers and the dimethylsiloxane derivatives are believed to reduce the surface energy of thecured liquid, therefore increasing the ability of the template torelease from the surface. The silylated monomers and dimethyl siloxanederivatives listed herein are all commercially available from Gelest,Inc.

[0112] Any material that may initiate a free radical reaction may beused as the initiator. For activating light curing of the curablematerial, it is preferred that the initiator is a photoinitiator.Examples of initiators include, but are not limited to,alpha-hydroxyketones (e.g., 1-hydroxycyclohexyl phenyl ketone, sold byCiba-Geigy Specialty Chemical Division as Irgacure 184), andacylphosphine oxide initiators (e.g., phenylbis(2,4,6-trimethyl benzoyl)phosphine oxide, sold by Ciba-Geigy Specialty Chemical Division asIrgacure 819).

[0113] The curable liquid may also include a crosslinking agent.Crosslinking agents are monomers that include two or more polymerizablegroups. In one embodiment, polyfunctional siloxane derivatives may beused as a crosslinking agent. An example of a polyfunctional siloxanederivative is 1,3-bis(3-methacryloxypropyl)-tetramethyl disiloxane.

[0114] In one example, a curable liquid may include a mixture of 50% byweight of n-butyl acrylate and 50% (3-acryloxypropyl)tris-trimethylsiloxane-silane. To this mixture 3% by weight mixture of a1:1 Irgacure 819 and Irgacure 184 and 5% of the crosslinker1,3-bis(3-methacryloxypropyl)-tetramethyl disiloxane may be added. Theviscosity of this mixture is less than 30 cps measured at about 25° C.

[0115] Curable Liquid with Gas Release

[0116] In an alternate embodiment, the curable liquid may be formed of amonomer, an acid-generating photo-agent, and a base-generatingphoto-agent. Examples of the monomer include, but are not limited to,phenolic polymers and epoxy resins. The acid-generating photo-agent is acompound that releases acid when treated with activating light. Thegenerated acid catalyzes polymerization of the monomer. Those ofordinary skill in the art know such acid-generating additives, and thespecific acid-generating additive used depends on the monomer and thedesired curing conditions. In general, the acid-generating additive isselected to be sensitive to radiation at the first wavelength λ₁, which,in some implementations, is in the visible or near ultraviolet (near UV)range. For example, in some implementations, the first wavelength λ₁, isselected to be approximately 400 nm or longer. A base generatingphoto-agent is also added to the monomer. The base-generatingphoto-agent may inhibit curing of the monomer near the interface of thetemplate. The base generating photo-agent may be sensitive to radiationat a second wavelength λ₂, yet inert or substantially inert to radiationat the first wavelength λ₁. Moreover, the second wavelength λ₂. shouldbe selected so that radiation at the second wavelength is primarilyabsorbed near the surface of the monomer at the interface with thetemplate and does not penetrate very far into the curable liquid. Forexample, in some implementations, a base generating additive that issensitive to radiation having a wavelength λ₂ in the deep UV range, inother words, radiation having a wavelength in the range of about 190-280nm, may be used.

[0117] According to an embodiment, a curable liquid that includes amonomer, an acid-generating photo-agent and a base-generatingphoto-agent is deposited onto a substrate. A template is brought intocontact with the curable liquid. The curable liquid is then exposed toradiation at a first wavelength λ₁ and a second wavelength λ₂ of lightat substantially the same time. Alternatively, the curing liquid may beexposed to the radiation at the second wavelength λ₂ and subsequently tothe radiation at the first wavelength λ₁. Exposure of the curable liquidto radiation at the second wavelength λ₂ produces an excess of base nearthe interface with the template. The excess base serves to neutralizethe acid that is produced by exposure of the curable liquid to radiationat the first wavelength λ₁, thereby inhibiting the acid from curing thecurable liquid. Since the radiation at the second wavelength λ₂ has ashallow penetration depth into the curable liquid, the base produced bythat radiation only inhibits curing of the curable liquid at or near theinterface with the template. The remainder of the curable liquid iscured by exposure to the longer wavelength radiation (λ₁,) whichpenetrates throughout the curable liquid. U.S. Pat. No. 6,218,316entitled “Planarization of Non-Planar Surfaces in Device Fabrication”describes additional details concerning this process and is incorporatedherein by reference.

[0118] In another embodiment, the curable liquid may include aphotosensitive agent which, when exposed, for example, to deep UVradiation, decomposes to produce one or more gases such as hydrogen(H₂), nitrogen (N₂), nitrous oxide (N₂O), sulfur tri-oxide (SO₃),acetylene (C₂H₂), carbon dioxide (CO₂), ammonia (NH₃) or methane (CH₄).Radiation at a first wavelength λ₁, such as visible or near UV, may beused to cure the curable liquid, and the deep UV radiation (λ₂) may beused to produce one or more of the foregoing gases. The generation ofthe gases produces localized pressure near the interface between thecured liquid and the template to facilitate separation of the templatefrom the cured liquid. U.S. Pat. No. 6,218,316 describes additionaldetails concerning this process and is incorporated herein by reference.

[0119] In another embodiment, a curable liquid may be composed of amonomer that cures to form a polymer that may be decomposed by exposureto light. In one embodiment, a polymer with a doubly substituted carbonbackbone is deposited on the substrate. After the template is broughtinto contact with the curable liquid, the curable liquid is exposed toradiation at a first wavelength λ₁ (e.g., greater than 400 nm) andradiation at the second wavelength λ₂ in the deep UV range. Radiation atthe first wavelength serves to cure the curable liquid. When the curableliquid is exposed to the second wavelength λ2, scission occurs at thesubstituted carbon atoms. Since deep UV radiation does not penetratedeeply into the curable liquid, the polymer decomposes only near theinterface with the template. The decomposed surface of the cured liquidfacilitates separation from the template. Other functional groups whichfacilitate the photo-decomposition of the polymer also can be used. U.S.Pat. No. 6,218,316 describes additional details concerning this processand is incorporated herein by reference.

[0120] Patterned Templates

[0121] In various embodiments, an imprint lithography template ismanufactured using processes including, but not limited to: opticallithography, electron beam lithography, ion-beam lithography, x-raylithography, extreme ultraviolet lithography, scanning probelithography, focused ion beam milling, interferometric lithography,epitaxial growth, thin film deposition, chemical etch, plasma etch, ionmilling, reactive ion etch or a combination of the above. Methods formaking patterned templates are described in U.S. patent application No.10/136,188 filed May 1, 2002 entitled “Methods of Manufacturing aLithography Template” to Voison which is incorporated herein byreference.

[0122] In an embodiment, the imprint lithography template issubstantially transparent to activating light. The template includes abody having a lower surface. The template further includes a pluralityof recesses on the lower surface extending toward the top surface of thebody. The recesses may be of any suitable size, although typically atleast a portion of the recesses has a feature size of less than about250 nm.

[0123] With respect to imprint lithography processes, the durability ofthe template and its release characteristics may be of concern. In oneembodiment, a template is formed from quartz. Other materials may beused to form the template and include, but are not limited to: silicongermanium carbon, gallium nitride, silicon germanium, sapphire, galliumarsinide, epitaxial silicon, poly-silicon, gate oxide, silicon dioxideor combinations thereof. Templates may also include materials used toform detectable features, such as alignment markings. For example,detectable features may be formed of SiO_(x), where X is less than 2. Insome embodiments, X is about 1.5. In another example, detectablefeatures may be formed of a molybdenum silicide. Both SiOx andmolybdenum silicide are optically transparent to light used to cure thepolymerizable liquid. Both materials, however, are substantially opaqueto visible light. Use of these materials allows alignment marks to becreated on the template that will not interfere with curing of theunderlying substrate.

[0124] As previously mentioned, the template is treated with a surfacetreatment material to form a thin layer on the surface of the template.A surface treatment process is optimized to yield a low surface energycoating. Such a coating is used in preparing imprint templates forimprint lithography. Treated templates have desirable releasecharacteristics relative to untreated templates. Untreated templatesurfaces possess surface free energies of about 65 dynes/cm or more. Atreatment procedure disclosed herein yields a surface treatment layerthat exhibits a high level of durability. Durability of the surfacetreatment layer allows a template to be used for numerous imprintswithout having to replace the surface treatment layer. The surfacetreatment layer, in some embodiments, reduces the surface free energy ofthe lower surface measured at 25° C. to less than about 40 dynes/cm, orin some cases, to less than about 20 dynes/cm.

[0125] A surface treatment layer, in one embodiment, is formed by thereaction product of an alkylsilane, a fluoroalkylsilane, or afluoroalkyltrichlorosilane with water. This reaction forms a silinatedcoating layer on the surface of the patterned template. For example, asilinated surface treatment layer is formed from a reaction product oftridecafluoro-1,1,2,2-tetrahydrooctyl trichlorosilane with water. Asurface treatment layer may be formed using either a liquid-phaseprocess or a vapor-phase process. In a liquid-phase process, thesubstrate is immersed in a solution of precursor and solvent. In avapor-phase process, a precursor is delivered via an inert carrier gas.It may be difficult to obtain a purely anhydrous solvent for use in aliquid-phase treatment. Water in the bulk phase during treatment mayresult in clump deposition, which will adversely affect the finalquality or coverage of the coating. In an embodiment of a vapor-phaseprocess, the template is placed in a vacuum chamber, after which thechamber is cycle-purged to remove excess water. Some adsorbed water,however, remains on the surface of the template. A small amount ofwater, however, is believed to be needed to initiate a surface reaction,which forms the coating. It is believed that the reaction may bedescribed by the formula:

R—SiCl₃ +3H₂O→R—Si(OH)₃ +3HCl

[0126] To facilitate the reaction, the template is brought to a desiredreaction temperature via a temperature-controlled chuck. The precursoris then fed into the reaction chamber for a prescribed time. Reactionparameters such as template temperature, precursor concentration, flowgeometries, etc. are tailored to the specific precursor and templatesubstrate combination. By controlling these conditions, the thickness ofthe surface treatment layer is controlled. The thickness of the surfacetreatment layer is kept at a minimal value to minimize the interferenceof the surface treatment layer with the feature size. In one embodiment,a monolayer of the surface treatment layer is formed.

[0127] Discontinuous Template

[0128] In an embodiment, there are at least two separate depthsassociated with the recesses on the lower surface of the template. FIGS.20A and 20 B depict top and cross-sectional views, respectively, of apatterned template with recesses having two depths. Referring to FIGS.20A and 20B, a template includes one or more patterning areas 401. Insuch embodiments, a first relatively shallow depth is associated withthe recesses in the patterning areas of the template, as depicted inFIG. 20B. The patterning area includes the area replicated duringpatterning of the template. The patterning areas are positioned within aregion defined by border 409 of the template. Border 409 is defined asthe region that extends from an outer edge of any of the patterningareas to an edge 407 of the template. The border has a depth that issubstantially greater than the depth of the recesses in the patterningareas. The perimeter of the template is herein defined as the boundarybetween the patterning areas and border 409. As depicted in FIG. 20Afour patterning areas are positioned within the area defined by thetemplate. The patterning areas are separated from edges 407 of thetemplate by border 409. The “perimeter” of the template is defined byedges 403 a, 403 b, 403 c, 403 d, 403 e, 403 f, 403 g, and 403 h of thepatterning areas.

[0129] The patterning areas may be separated from each other by channelregions 405. Channel regions are recesses that are positioned betweenthe patterning areas that have a greater depth than the recesses of thepattering areas. As described below, both border regions and channelregions inhibit the flow of liquid between the patterning regions orbeyond the perimeter of the patterning areas, respectively.

[0130] The design of the template is chosen based on the type oflithography process used. For example, a template for positive imprintlithography has a design that favors the formation of discontinuousfilms on the substrate. In one embodiment, a template 12 is formed suchthat the depth of one or more structures is relatively large compared tothe depth of structures used to form the patterning region, as depictedin FIG. 15. During use, template 12 is placed in a desired spacedrelationship to substrate 20. In such an embodiment, the gap (h₁)between the lower surface 536 of template 12 and substrate 20 is muchsmaller than the gap (h₂) between recessed surface 534 and substrate 20.For example, h₁ may be less than about 200 nm, while h₂ may be greaterthan about 10,000 nm. When the template is brought into contact withliquid 40 on substrate 20, liquid 40 leaves the region under recessedsurface 534 and fills the gap between lower surface 536 and substrate 20(as depicted in FIG. 16). It is believed that combinations of surfaceenergies and capillary forces draw the liquid from the larger recessinto the narrower region. As hi is decreased, forces applied to theliquid by template 12 may overcome capillary forces drawing the liquidunder lower surface 536. These forces may cause spreading of the liquidinto the area under recessed surface 534. The minimum value of h₁ atwhich the liquid is inhibited from spreading into a recess 532 isreferred to herein as the “minimum film thickness.” Additionally, as h₁increases, the capillary forces are reduced, eventually allowing theliquid to spread into the deeper recessed regions. The maximum value ofh₁ at which the capillary forces are sufficient to inhibit flow ofliquid into the deeper recessed region is herein known as the “maximumfilm thickness.”

[0131] As depicted in FIGS. 17 and 18, in various embodiments, template12 is formed such that a curable liquid placed on substrate 20 isinhibited from flowing beyond perimeter 412 of template 12. In theembodiment depicted in FIG. 17, height hi is measured from substrate 20to shallow recessed surface 552. Shallow recessed surface 552 extends tothe perimeter of template 12. Thus, the edge of the template forms theheight h₂ and is effectively infinite in comparison to height h₁. In theembodiment depicted in FIG. 18, a deep recess is formed at the outeredge of template 12. Height h₂ is measured between substrate 20 and deeprecessed surface 554. Height h₁ is again measured between substrate 20and shallow recessed surface 552. In either embodiment, height h₂ ismuch larger than height h₁. If h₁ is small enough, the activating lightcurable liquid remains in the gap between template 12 and substrate 20while a curing agent is applied. Deeply recessed portions areparticularly useful for liquid confinement in step and repeat processesas described herein.

[0132] In an embodiment, template 12 and substrate 20 each have one ormore alignment marks. Alignment marks may be used to align template 12and substrate 20. For example, one or more optical imaging devices(e.g., microscopes, cameras, imaging arrays, etc.) are used to determinealignment of the alignment marks.

[0133] In some embodiments, an alignment mark on the template may besubstantially transparent to activating light. Alternatively, thealignment mark may be substantially opaque to alignment mark detectionlight. As used herein, alignment mark detection light and light used forother measurement and analysis purposes is referred to as “analyzinglight.” In an embodiment, analyzing light includes, but is not limitedto: visible light and/or infrared light. The alignment mark may beformed of a material different than the material of the body. Forexample, the alignment mark may be formed from SiO_(x) where x is about1.5. In another example, the alignment mark may be formed of molybdenumsilicide. Alternately, the alignment mark may include a plurality oflines etched on a surface of the body. The lines are configured tosubstantially diffuse activating light, but produce an analyzable markunder analyzing light.

[0134] In various embodiments, one or more deep recesses as describedabove may project entirely through the body of the template to formopenings in the template. An advantage of such openings is that they mayeffectively ensure that height h₂ is very large with respect to h₁ ateach opening. Additionally, in some embodiments, pressurized gas orvacuum may be applied to the openings. Pressurized gas or vacuum mayalso be applied to one or more openings after curing the liquid. Forexample, pressurized gas may be applied after curing as part of a peeland pull process to assist in separating the template from the curedliquid.

[0135] Alternate System Embodiments

[0136] The above described imprint lithography system may be modifiedaccording to alternate embodiments discussed below. It should beunderstood that any of the described alternative embodiments may becombined, singly or in combination, with any other system describedherein.

[0137] As described above, an imprint head includes a fine orientationsystem that allows for a “passive” orientation of the template withrespect to the substrate. In another embodiment, fine orientation systemmay include actuators coupled to the flexure arms. The actuators mayallow “active” control of the fine orientation system. During use anoperator or a programmable controller monitors the orientation of thetemplate with respect to the substrate. The operators or a programmablecontroller then alters the orientation of the template with respect tothe substrate by operating the actuators. Movement of the actuatorscauses motion of the flexure arms to alter the orientation of thetemplate. In this manner an “active” control of fine positioning of thetemplate with respect to the substrate may be achieved. An active fineorientation system is further described in U.S. Ser. No. 09/920,341filed Aug. 1, 2001 entitled “Methods for High-Precision Gap OrientationSensing Between a Transparent Template and Substrate for ImprintLithography” which is incorporated herein by reference.

[0138] In an alternate embodiment, imprint head may include apre-calibration system, as described above. Pre-calibration systemincludes a flexure ring 3124 as depicted in FIG. 21. In place of thefine orientation system as described above, a template support system3125 is coupled to pre-calibration ring. In contrast to the fineorientation system, template support system 3125 is formed ofsubstantially rigid and non-compliant members 3127. These membersprovide a substantially rigid support for a template 3700 disposed intemplate support 3130. In this embodiment, fine orientation may beachieved using motion stage instead of template support.

[0139] In previous embodiments, imprint head 3100 is coupled to the bodyin a fixed position. In an alternate embodiment, imprint head 3100 maybe mounted to a motion system that allows the imprint head to be movedalong the X-Y plane, as depicted in FIG. 22. Imprint head 3100 isconfigured to support a patterned template as described in any of theembodiments herein. Imprint head 3100 is coupled to a motion system thatincludes an imprint head chuck 3121 and a imprint motion stage 3123.Imprint head 3100 is mounted to imprint head chuck 3121. Imprint headchuck interacts with imprint motion stage 3123 to move imprint headalong an X-Y plane. Mechanical or electromagnetic motion systems may beused. Electromagnetic systems rely on the use of magnets to produce anX-Y planar motion the imprint chuck. Generally, an electromagneticsystem incorporates permanent and electromagnetic magnets into theimprint motion stage 3123 and the imprint head chuck 3121. Theattractive forces of these magnets is overcome by a cushion of airbetween imprint head chuck 3121 and imprint head motion stage 3123 suchthat an “air bearing” is produced. Imprint head chuck, and therefore theimprint head, is moved along an X-Y plane on a cushion of air.Electromagnetic X-Y motion stages are described in further detail inU.S. Pat. No. 6,389,702, entitled “Method and Apparatus for MotionControl,” which is incorporated herein by reference. In a mechanicalmotion system, imprint head chuck is attached to a motion stage. Themotion stage is then moved by use of various mechanical means to alterthe position of the imprint head chuck, and thus the imprint head, alongthe X-Y plane. In this embodiment, imprint head may include a passivecompliant fine orientation system, an actuated fine orientation system,or a rigid template support system, as described herein.

[0140] With imprint head 3100 coupled to a moving support, the substratemay be mounted to a stationary support. Thus, in an alternateembodiment, imprint head 3100 is coupled to an X-Y axis motion stage asdescribed herein. A substrate is mounted to a substantially stationarysubstrate support. A stationary substrate support is depicted in FIG.40. Stationary substrate support 3640 includes a base 3642 and asubstrate chuck 3644. Substrate chuck 3644 is configured to support asubstrate during imprint lithography processes. Substrate chuck mayemploy any suitable means to retain a substrate to the substrate chuck.In one embodiment, substrate chuck 3644 may include a vacuum systemwhich applies a vacuum to the substrate to couple the substrate to thesubstrate chuck. Substrate chuck 3644 is coupled to a base 3642. Base3642 is coupled to support 3920 of an imprint lithography system (SeeFIG. 1). During use, stationary substrate support 3640 remains in afixed position on support 3920 while the imprint head position is variedto access different portions of the substrate.

[0141] Coupling an imprint head to a motion stage can offer advantagesover techniques in which the substrate is on a motion stage. Motionstages generally rely on an air bearing to allow substantiallyfrictionless motion of the motion stage. Generally, motion stages arenot designed to accommodate significant pressure applied along theZ-axis. When pressure is applied to a motion stage chuck along theZ-axis, the motion stage chuck position will change slightly in responseto this pressure. During a step and repeat process, a template that hasa smaller area than the area of the substrate is used to form multipleimprinted areas. The substrate motion stage is relatively large comparedto the template, to accommodate the larger substrates. When a templatecontacts the substrate motion stage in a position that is off-center,the motion stage will tilt to accommodate the increased pressure. Thistilt is compensated for by tilting the imprint head to ensure properalignment. If, however, the imprint head is coupled to the motion stage,all of the forces along the Z-axis will be centers on the template,regardless of where on the substrate the imprinting is taking place.This leads to increased ease in alignment and may also increase thethroughput of the system.

[0142] In an embodiment, a substrate tilt module may be formed in asubstrate support as depicted in FIG. 39. Substrate support 3650includes a substrate chuck 3652, coupled to a substrate tilt module3654. Substrate tilt module 3654 is coupled to a base 3656. Base 3656,in one embodiment, is coupled to a motion stage which allows X-Y motionof the substrate support. Alternatively, base 3656 is coupled to asupport (e.g., 3920) such that the substrate support is mounted to animprint system in a fixed position.

[0143] Substrate chuck 3652 may employ any suitable means to retain asubstrate to the substrate chuck. In one embodiment, substrate chuck3654 may include a vacuum system which applies a vacuum to the substrateto couple the substrate to the substrate chuck. Substrate tilt module3654 includes a flexure ring 3658 coupled to flexure ring support 3660.A plurality of actuators 3662 are coupled to flexure ring 3658 andflexure ring support 3660. Actuators 3662 are operated to alter the tiltof flexure ring 3658. Actuators, in one embodiment, use a differentialgear mechanism that may be manually or automatically operated. In analternate embodiment, actuators use an eccentric roller mechanism. Aneccentric roller mechanism generally provides more vertical stiffness tothe substrate support than a differential gear system. In oneembodiment, substrate tilt module has a stiffness that will inhibit tiltof the substrate when the template applies a force of between about 1lb. to about 10 lbs. to a liquid disposed on the substrate.Specifically, substrate tilt module is configured to allow no more than5 micro radians of tilt when pressure up to about 10 lbs. are applied tothe substrate through the liquid on the template.

[0144] During use sensors coupled to the substrate chuck may be used todetermine the tilt of the substrate. The tilt of the substrate isadjusted by actuators 3662. In this manner tilt correction of thesubstrate may be achieved.

[0145] Substrate tilt module may also include a fine orientation system.A substrate support that includes a fine orientation system is depictedin FIG. 42. To achieve fine orientation control, flexure ring 3658includes a central recess in which substrate chuck 3652 is disposed. Thedepth of the central recess is such that an upper surface of a substratedisposed on substrate chuck 3652 is substantially even with an uppersurface of flexure ring 3658. Fine orientation may be achieved usingactuators 3662. Fine orientation is achieved by the use of actuatorscapable of controlled motion in the nanometer range. Alternatively, fineorientation may be achieved in a passive manner. Actuators may besubstantially compliant. The compliance of the actuators may allow thesubstrate to self-correct for variations in tilt when a template is incontact with a liquid disposed on a substrate surface. By disposing thesubstrate in a position that is substantially even with the flexurering, fine orientation may be achieved at the substrate-liquid interfaceduring use. Compliance of actuators is thus transferred to the uppersurface of the substrate to allow fine orientation of the substrate.

[0146] The above described systems are generally configured to systemsin which an activating light curable liquid is dispensed onto asubstrate and the substrate and template are brought into proximity toeach other. It should be understood, however, that the above-describedsystems may be modified to allow an activating light curable liquid tobe applied to a template rather than the substrate. In such anembodiment, the template is placed below the substrate. FIG. 41 depictsa schematic drawing of an embodiment of a system 4100 that is configuredsuch that the template is positioned below a substrate. System 4100includes an imprint head 4110 and a substrate support 4120 positionedabove imprint head 4110. Imprint head is configured to hold a template3700. Imprint head may have a similar in design to any of the hereindescribed imprint heads. For example, imprint head 4110 may include afine orientation system as described herein. Imprint head is be coupledto imprint head support 4130. Imprint head may be coupled in a fixedposition and remain substantially motionless during use. Alternatively,imprint head may be placed on a motion stage that allows X-Y planarmotion of imprint head 4130 during use.

[0147] The substrate to be imprinted is mounted onto a substrate support4120. Substrate support 4120 has a similar design to any of the hereindescribed substrate supports. For example, substrate support 4120 mayinclude a fine orientation system as described herein. Substrate support4120 may be coupled to a support 4140 in a fixed position and remainsubstantially motionless during use. Alternatively, substrate support4120 may be placed on a motion stage that allows X-Y planar motion ofsubstrate support during use.

[0148] During use an activating light curable liquid is placed on atemplate 3700 disposed in imprint head. The template may be patterned orplanar, depending on the type of operation to be perfonmed. Patternedtemplates may be configured for use in positive, negative, orcombinations of positive and negative imprint lithography systems asdescribed herein.

Imprint Lithography Process

[0149] Negative Imprint Lithography Process

[0150] A typical imprint lithography process is shown in FIGS. 23A-23F.As depicted in FIG. 23A, template 12 is positioned in a spaced relationto the substrate 20 such that a gap is formed between template 12 andsubstrate 20. Template 12 may include a surface that defines one or moredesired features, which may be transferred to the substrate 20 duringpatterning. As used herein, a “feature size” generally refers to awidth, length and/or depth of one of the desired features. In variousembodiments, the desired features may be defined on the surface oftemplate 12 as recesses and or a conductive pattern formed on a surfaceof the template. Surface 14 of template 12 may be treated with a thinlayer 13 that lowers the template surface energy and assists inseparation of template 12 from substrate 20. Surface treatment layersfor templates are described herein.

[0151] In an embodiment, substance 40 may be dispensed upon substrate 20prior to moving template 12 into a desired position relative tosubstrate 20. Substance 40 may be a curable liquid that conforms to theshape of desired features of template 12. In an embodiment, substance 40is a low viscosity liquid that at least partially fills the space of gap31 without the use of high temperatures. Low viscosity liquids may alsoallow the gap between the template and the substrate to be closedwithout requiring high pressures. As used herein the term “low viscosityliquids” refer to liquids having a viscosity of less than about 30centipoise measured at about 25° C. Further details regardingappropriate selections for substance 40 are discussed below. Template 12may interact with curable liquid 40 to conform the liquid into a desireshape. For example, curable liquid 40 may conform to the shape oftemplate 12 as depicted in FIG. 23B. The position of template 12 may beadjusted to create a desired gap distance between the template andsubstrate 20. The position of template 12 may also be adjusted toproperly align the template with the substrate.

[0152] After template 12 is properly positioned, substance 40 is curedto form a masking layer 42 on the substrate. In an embodiment, substance40 is cured using activating light 32 to form masking layer 42.Application of activating light through template 12 to cure the liquidis depicted in FIG. 23C. After the liquid is substantially cured,template 12 is removed from masking layer 42, leaving the cured maskinglayer on the surface of substrate 20, as depicted in FIG. 23D. Maskinglayer 42 has a pattern that is complementary to the pattern of template12. Masking layer 42 may include a “base layer” (also called a “residuallayer”) between one or more desired features. The separation of template12 from masking layer 42 is done so that desired features remain intactwithout shearing or tearing from the surface of substrate 20. Furtherdetails regarding separation of template 12 from substrate 20 followingimprinting are discussed below.

[0153] Masking layer 42 may be used in a variety of ways. For example,in some embodiments, masking layer 42 may be a functional layer. In suchembodiments, curable liquid 40 may be curable to form a conductivelayer, a semiconductive layer, a dielectric layer and/or a layer havinga desired mechanical or optical property. In another embodiment, maskinglayer 42 may be used to cover portions of substrate 20 during furtherprocessing of substrate 20. For example, masking layer 42 may be usedduring a material deposition process to inhibit deposition of thematerial on certain portions of the substrate. Similarly, masking layer42 may be used as a mask for etching substrate 20. To simplify furtherdiscussion of masking layer 42, only its use as a mask for an etchingprocess will be discussed in embodiments described below. However, it isrecognized that masking layers in embodiments described herein may beused in a variety of processes as previously described.

[0154] For use in an etch process, masking layer 42 may be etched usingan etch process until portions of substrate 20 are exposed throughmasking layer 42, as depicted in FIG. 23E. That is, portions of the baselayer may be etched away. Portions 44 of masking layer 42 may remain onsubstrate 20 for use in inhibiting etching of portions of substrate 20.After etching of masking layer 42 is complete, substrate 20 may beetched using known etching processes. Portions of substrate 20 disposedunder portions 44 of masking layer 42 may remain substantially unetchedwhile the exposed portions of substrate 20 are etched. In this manner, apattern corresponding to the pattern of template 12 may be transferredto substrate 20. The remaining portions 44 of masking layer 42 may beremoved leaving a patterned substrate 20, depicted in FIG. 23F.

[0155] FIGS. 24A-24D illustrate an embodiment of an imprint lithographyprocess using a transfer layer. A transfer layer 18 may be formed uponan upper surface of substrate 20. Transfer layer 18 may be formed from amaterial that has different etch characteristics than underlyingsubstrate 20 and/or a masking layer formed from a curable liquid 40.That is, each layer (e.g., transfer layer 18, masking layer and/orsubstrate 20) may be etched at least somewhat selectively with respectto the other layers.

[0156] A masking layer 44 is formed on the surface of transfer layer 18by depositing a curable liquid on the surface of transfer layer 18 andcuring the masking layer as described with reference to FIGS. 23A-23C.Masking layer 42 may be used as a mask for etching transfer layer 18.Masking layer 42 is etched using an etch process until portions oftransfer layer 18 are exposed through masking layer 42, as depicted inFIG. 24B. Portions 44 of masking layer 42 remain on transfer layer 18and may be used to inhibit etching of portions of the transfer layer.After etching of masking layer 42 is complete, transfer layer 18 may beetched using known etching processes. Portions of transfer layer 18disposed under portions 44 of masking layer 42 may remain substantiallyunetched while the exposed portions of transfer layer 18 are etched. Inthis manner, the pattern of masking layer 42 is replicated in transferlayer 18.

[0157] In FIG. 24C, portions 44 and etched portions of transfer layer 18together form a masking stack 46 that may be used to inhibit etching ofportions of the underlying substrate 20. Etching of substrate 20 may beperformed using a known etch process (e.g., a plasma etching process, areactive ion etching process, etc.). As depicted in FIG. 24D, themasking stack may inhibit etching of the underlying portions ofsubstrate 20. Etching of the exposed portions of substrate 20 may becontinued until a predetermined depth is reached. An advantage of usinga masking stack as a mask for etching of substrate 20 is that thecombined stack of layers may create a high aspect ratio mask (i.e., amask that has a greater height than width). A high aspect ratio maskinglayer may be desirable during the etching process to inhibitundercutting of the mask portions.

[0158] The processes depicted in FIGS. 23A-23F and FIGS. 24A-24D areexamples of negative imprint lithography processes. As used herein a“negative imprint lithography” process generally refers to a process inwhich the curable liquid is substantially conformed to the shape of thetemplate before curing. That is, a negative image of the template isformed in the cured liquid. As depicted in these figures, thenon-recessed portions of the template become the recessed portions ofthe mask layer. The template, therefore, is designed to have a patternthat represents a negative image of the pattern to be imparted to themask layer.

[0159] Positive Imprint Lithography

[0160] As used herein a “positive imprint lithography” process generallyrefers to a process in which the pattern formed in the mask layer is amirror image of the pattern of the template. As will be furtherdescribed below, the non-recessed portions of the template become thenon-recessed portions of the mask layer.

[0161] A typical positive imprint lithography process is shown in FIGS.25A-25D. As depicted in FIG. 25A, template 12 is positioned in a spacedrelation to the substrate 20 such that a gap is formed between template12 and substrate 20. Surface of template 12 may be treated with a thinsurface treatment layer 13 that lowers the template surface energy andassists in separation of template 12 from the cured masking layer.

[0162] A curable liquid 40 is disposed on the surface of substrate 20.Template 12 is brought into contact with curable liquid 40. As depictedin FIG. 25B, the curable liquid fills the gap between the lower surfaceof the template and the substrate. In contrast to a negative imprintlithography process, curable liquid 40 is substantially absent fromregions of the substrate approximately below at least a portion of therecesses of the template. Thus, curable liquid 40 is maintained as adiscontinuous film on the substrate that is defined by the location ofat least a portion of the recesses of template 12. After template 12 isproperly positioned, curable liquid 40 is cured to form a masking layer42 on the substrate. Template 12 is removed from masking layer 42,leaving the cured masking layer on the surface of substrate 20, asdepicted in FIG. 25C. Masking layer 42 has a pattern that iscomplementary to the pattern of template 12. Masking layer 42 may beused to inhibit etching of portions of substrate 20. After formation ofmasking layer 42 is complete, substrate 20 may be etched using knownetching processes. Portions of substrate 20 disposed under masking layer42 may remain substantially unetched while the exposed portions ofsubstrate 20 are etched, as depicted in FIG. 25D. In this manner, thepattern of template 12 may be replicated in substrate 20. The remainingportions 44 of masking layer 42 may be removed to create a patternedsubstrate 20.

[0163] FIGS. 26A-26C illustrate an embodiment of a positive imprintlithography process using a transfer layer. A transfer layer 18 may beformed upon an upper surface of a substrate 20. Transfer layer 18 isformed from a material that has different etch characteristics than theunderlying transfer layer 18 and/or substrate 20. A masking layer 42 isformed on the surface of transfer layer 18 by depositing a curableliquid on the surface of transfer layer 18 and curing the masking layeras described with reference to FIGS. 25A-25C.

[0164] Masking layer 42 may be used as a mask for etching transfer layer18. Masking layer 42 may inhibit etching of portions of transfer layer18. Transfer layer 18 may be etched using known etching processes.Portions of transfer layer 18, disposed under masking layer 42 mayremain substantially unetched while the exposed portions of transferlayer 18 are etched. In this manner, the pattern of masking layer 42 maybe replicated in transfer layer 18.

[0165] In FIG. 26B, masking layer 42 and etched portions of transferlayer 18 together form a masking stack 46 that may be used to inhibitetching of portions of the underlying substrate 20. Etching of substrate20 may be performed using known etching processes (e.g., a plasmaetching process, a reactive ion etching process, etc.). As depicted inFIG. 26C, the masking stack may inhibit etching of the underlyingportions of substrate 20. Etching of the exposed portions of substrate20 may be continued until a predetermined depth is reached.

[0166] Positive/Negative Imprint Lithography

[0167] In an embodiment, a process may combine positive and negativeimprint lithography. A template for a combined positive and negativeimprint lithography process may include recesses suitable for positivelithography and recesses suitable for negative lithography. For example,an embodiment of a template for combined positive and negative imprintlithography is depicted in FIG. 27A. Template 12, as depicted in FIG.27A, includes a lower surface 566, at least one first recess 562, and atleast one second recess 564. First recess 562 is configured to create adiscontinuous portion of curable liquid 40 when the template contactsthe curable liquid. A height of first recess (h₂) is substantiallygreater than a height of second recess (h₁).

[0168] A typical combined imprint lithography process is shown in FIGS.27A-27E. As depicted in FIG. 27A, template 12 is positioned in a spacedrelation to the substrate 20 such that a gap is formed between template12 and substrate 20. At least the lower surface 566 of template 12 maybe treated with a thin surface treatment layer (not shown) that lowersthe template surface energy and assists in separation of template 12from the cured masking layer. Additionally, surfaces of first recesses562 and/or second recesses 564 may be treated with the thin surfacetreatment layer.

[0169] A curable liquid 40 is disposed on the surface of substrate 20.Template 12 is brought into contact with curable liquid 40. As depictedin FIG. 27B, the curable liquid fills the gap between the lower surfaceof the template 566 and substrate 20. Curable liquid 40 also fills firstrecesses 562. However, curable liquid 40 is substantially absent fromregions of the substrate approximately below second recesses 564. Thus,curable liquid 40 is maintained as a discontinuous film on the substratethat includes surface topography corresponding to the pattern formed byfirst recesses 562. After template 12 is properly positioned, curableliquid 40 is cured to form a masking layer 42 on the substrate. Template12 is removed from masking layer 42, leaving the cured masking layer onthe surface of substrate 20, as depicted in FIG. 27C. Mask layer 42 mayinclude a region 568 that resembles a mask layer formed by negativeimprint lithography. In addition, mask layer 42 may include a region 569that does not include any masking material.

[0170] In one embodiment, mask layer 42 is composed of a material thathas the same or a similar etch rate as the underlying substrate. An etchprocess is be applied to masking layer 42 to remove the masking layerand substrate at substantially the same etch rate. In this manner themultilayer pattern of the template may be transferred to the substrate,as depicted in FIG. 27D. This process may also be performed using atransfer layer as described in other embodiments.

[0171] A combination of positive and negative lithography is also usefulfor patterning multiple regions of a template. For example, a substratemay include a plurality of regions that require patterning. As depictedin FIG. 27C, a template with multiple depth recesses includes twopatterning regions 568 with an intervening “channel” region 569. Channelregion 569 inhibits flow of a liquid beyond the patterning area of thetemplate.

[0172] Step and Repeat

[0173] As used herein, a “step and repeat” process refers to using atemplate smaller than the substrate to form a plurality of patternedregions on the substrate. A step and repeat imprint process includesdepositing a light curable liquid on a portion of a substrate, aligninga pattern in the cured liquid to previous patterns on the substrate,impressing a template into the liquid, curing the liquid, and separatingthe template from the cured liquid. Separating the template from thesubstrate may leave an image of the topography of the template in thecured liquid. Since the template is smaller than the total surface areaof the substrate, only a portion of the substrate includes the patternedcured liquid. The “repeat” portion of the process includes depositing alight curable liquid on a different portion of the substrate. Apatterned template is then aligned with the substrate and contacted withthe curable liquid. The curable liquid is cured using activating lightto form a second area of cured liquid. This process may be continuallyrepeated until most of the substrate is patterned. Step and repeatprocesses may be used with positive, negative, or positive/negativeimprint processes. Step and repeat processes may be performed with anyembodiments of equipment described herein.

[0174] Step and repeat imprint lithography processes offer a number ofadvantages over other techniques. Step and repeat processes describedherein are based on imprint lithography that uses low viscosity lightcurable liquids and rigid, transparent templates. The templates aretransparent to liquid activating light and alignment mark detectionlight thus offering the potential for layer-to-layer alignment. Forproduction-scale imprint lithography of multi-level devices, it isadvantageous to possess very high-resolution layer-to-layer alignment(e.g., as low as ⅓^(rd) of the minimum feature size (“MFS”)).

[0175] There are various sources of distortion errors in making of thetemplates. Step and repeat processes are used so that only a portion ofa substrate is processed during a given step. The size of the fieldprocessed during each step should be small enough to possess patterndistortions of less than ⅓^(rd) the MFS. This necessitates step andrepeat patterning in high-resolution imprint lithography. This is alsothe reason why most optical lithography tools are step and repeatsystems. Also, as discussed before, a need for low CD variations anddefect inspection/repair also favors processing of small fields.

[0176] In order to keep process costs low, it is important forlithography equipment to possess sufficiently high throughput.Throughput requirements put a stringent limit on the patterning timeallowed per field. Low viscosity liquids that are light curable areattractive from a throughput point of view. These liquids move muchfaster to properly fill the gap between the template and the substrateand the lithography capability is pattern independent. The resulting lowpressure, room temperature processing is suitable for high throughput,while retaining the benefits of layer-to-layer alignment.

[0177] While prior inventions have addressed patterning of low viscositylight curable liquids, they have not addressed this for a step andrepeat process. In photolithography as well as in hot embossing, a filmis spin coated and hard baked onto the substrate prior to itspatterning. If such an approach is used with low viscosity liquids,there are three major problems. Low viscosity liquids are difficult tospin coat since they tend to de-wet and cannot retain the form of acontinuous film. Also, in a step and repeat process, the liquidundergoes evaporation thereby causing varying amounts of liquid to beleft behind on the substrate as the template steps and repeats over thesubstrate. Finally, a blanket light exposure tends to disperse beyondthe specific field being patterned. This tends to cause partial curingof the subsequent field, thereby affecting the fluid properties of theliquid prior to imprinting. An approach that dispenses liquid suitablefor a single field onto the substrate, one field at a time, may solvethe above three problems. However, it is important to accurately confinethe liquid to that particular field to avoid loss of usable area on thesubstrate.

[0178] In general, lithography is one of many unit processes used in theproduction of devices. The cost of all these processes, particularly inmulti-layer devices, makes it highly desirable to place patternedregions as close as possible to each other without interfering withsubsequent patterns. This effectively maximizes the usable area andhence the usage of the substrate. Also, imprint lithography may be usedin a “mix-and-match” mode with other kinds of lithography (such asoptical lithography) wherein different levels of the same device aremade from different lithography technologies. It is advantageous to makethe imprint lithography process compatible with other lithographytechniques. A “kerf” region is the region that separates two adjacentfields on a substrate. In state-of-the-art optical lithography toolsthis kerf region may be as small as 50-100 microms. The size of the kerfis typically limited by the size of the blades used to separate thepatterned regions. This small kerf region is expected to get smaller asthe dicing blades that dice the individual chips get thinner. In orderto accommodate this stringent kerf size requirement, the location of anyexcess liquid that is expelled from the patterned area should be wellconfined and repeatable. As such, the individual components, includingthe template, substrate, liquid and any other materials that affect thephysical properties of the system, including but not limited to surfaceenergy, interfacial energies, Hamacker constants, Van der Waals' forces,viscosity, density, opacity, etc., are engineered as described herein toproperly accommodate a repeatable process.

[0179] Formation of Discontinuous Films

[0180] As discussed previously, discontinuous films are formed using anappropriately patterned template. For example, a template with highaspect ratio recesses that define a border region can inhibit the flowof a liquid beyond the border area. The inhibition of the liquid withina border area is influenced by a number of factors. As discussed abovetemplate design plays a role in the confinement of a liquid.Additionally, the process by which the template is contacted with theliquid also influences the confinement of the liquid.

[0181] FIGS. 19 A-C depict a cross-sectional view of a process whereindiscontinuous films are formed on a surface. In one embodiment, acurable liquid 40 is dispensed onto a substrate 20 as a pattern of linesor droplets, as depicted in FIG. 19A. Curable liquid 40, therefore, doesnot cover an entire area of substrate 20 to be imprinted. As the lowersurface 536 of template 12 contacts liquid 40, the force of the templateon the liquid causes the liquid to spread over the surface of substrate20, as depicted in FIG. 19B. Generally, the more force that is appliedby the template to the liquid, the further the liquid will spread overthe substrate. Thus, if a sufficient amount of force is applied, theliquid may be forced beyond a perimeter of the template, as depicted inFIG. 19C. By controlling the forces applied to the liquid by thetemplate the liquid is confined within the predetermined borders of thetemplate, as depicted in FIG. 19D.

[0182] The amount of force applied to the liquid is related to theamount of liquid dispensed on the substrate and the distance thetemplate is from the substrate during curing. For a negative imprintlithography process the amount of fluid dispensed onto the substrateshould be less than or equal to a volume defined by: the volume ofliquid required to substantially fill the recesses of the patternedtemplate, the area of the substrate to be patterned, and the desiredthickness of the cured layer. If the amount of cured liquid exceeds thisvolume, the liquid will be displaced from the perimeter of the templatewhen the template is brought to the appropriate distance from thesubstrate. For a positive imprint lithography process the amount ofliquid dispensed onto the substrate should be less than the volumedefined by: the desired thickness of the cured layer (i.e., the distancebetween the non-recessed portions of the template and the substrate andthe surface area of the portion of the substrate to be patterned.

[0183] For an imprint lithography processes that uses a template thatincludes a border, the distance between the non-recessed surface of thetemplate and the substrate is set between the minimum film thickness andthe maximum film thickness, as previously described. Setting the heightbetween these values allows the appropriate capillary forces to containthe liquid within the border defined areas of the template.Additionally, the thickness of the layer should be approximatelycomparable to the height of the patterned features. If the cured layeris too thick, the features formed in the cured layer may be erodedbefore the features can be transferred to the underlying substrate. Itis therefore desirable to control the volume as described above to fallto allow the appropriate film thickness to be used.

[0184] The force applied by the template to the liquid is alsoinfluenced by the rate at which the template is brought into contactwith the liquid. Generally, the faster the template is brought intocontact the more force is applied to the liquid. Thus, some measure ofcontrol of the spread of liquid on the surface of the substrate may beachieved by controlling the rate at which the template is brought intocontact with the liquid.

[0185] All of these features are considered when positioning thetemplate with respect to the substrate for an imprint lithographyprocess. By controlling these variables in a predetermined manner, theflow of liquid may be controlled to stay confined within a predeterminearea.

[0186] Alignment Techniques

[0187] Overlay alignment schemes include measurement of alignment errorsfollowed by compensation of these errors to achieve accurate alignmentof a patterned template and a desired imprint location on a substrate.Correct placement of the template with respect to the substrate isimportant for achieving proper alignment of the patterned layer with anypreviously formed layers on the substrate. Placement error, as usedherein, generally refers to X-Y positioning errors between a templateand substrate (that is, translation along the X and/or Y-axis).Placement errors, in one embodiment, are determined and corrected for byusing a through the template optical device, as depicted in FIG. 14.

[0188]FIG. 28 illustrates a schematic diagram of an optical system 3820of through the template optical imaging system 3800 (See also FIG. 14).Optical system 3820 is configured to focus two alignment marks fromdifferent planes onto a single focal plane. Optical system 3820 may usethe change of focal length resulting from light with distinctwavelengths to determine the alignment of the template with anunderlying substrate. Optical system 3820 may include an optical imagingdevice 3810, an illumination source (not shown), and a focusing device3805. Light with distinct wavelengths may be generated either by usingindividual light sources or by using a single broad band light sourceand inserting optical band-pass filters between the imaging plane andthe alignment marks. Depending on the gap between the template 3700 andsubstrate 2500, different wavelengths are selected to adjust the focallengths. Under each wavelength of light used, each overlay mark mayproduce two images on the imaging plane as depicted in FIG. 29. A firstimage 2601, using a specific wavelength of light, is a clearly focusedimage. A second image 2602, using the same wavelength of light, is anout-of-focus image. In order to eliminate each out-of-focus image,several methods may be used.

[0189] In a first method, under illumination with a first wavelength oflight, two images may be received by optical imaging device 3810. Imagesare depicted in FIG. 29 and generally referenced by numeral 2604. Whileimages are depicted as squares, it should be understood that any othershape may be used, including crosses. Image 2602 corresponds to anoverlay alignment mark on the substrate. Image 2601 corresponds to anoverlay alignment mark on the template. When image 2602 is focused,image 2601 is out of focus. In an embodiment, an image processingtechnique may be used to erase geometric data corresponding to pixelsassociated with image 2602. Thus, the out of focus image of thesubstrate mark may be eliminated, leaving only image 2601. Using thesame procedure and a second wavelength of light, image 2605 and 2606 maybe formed on optical imaging device 3810. The out of focus image 2606 isthen eliminated, leaving only image 2605. The two remaining focusedimages 2601 and 2605 are then combined onto a single imaging plane 2603for making overlay error measurements.

[0190] A second method may utilize two coplanar polarizing arrays, asdepicted in FIG. 30, and polarized illumination sources. FIG. 30illustrates overlay marks 2701 and orthogonally polarized arrays 2702.Polarizing arrays 2702 are formed on the template surface or placedabove the surface. Under two polarized illumination sources, onlyfocused images 2703 (each corresponding to a distinct wavelength andpolarization) may appear on the imaging plane. Thus, out of focus imagesare filtered out by polarizing arrays 2702. An advantage of this methodmay be that it may not require an image processing technique toeliminate out-focused images.

[0191] Moire pattern based overlay measurement has been used for opticallithography processes. For imprint lithography processes, where twolayers of Moire patterns are not on the same plane but still overlappedin the imaging array, acquiring two individual focused images may bedifficult to achieve. However, carefully controlling the gap between thetemplate and substrate within the depth of focus of the opticalmeasurement tool and without direct contact between the template andsubstrate may allow two layers of Moire patterns to be simultaneouslyacquired with minimal focusing problems. It is believed that otherstandard overlay schemes based on the Moire patterns may be directlyimplemented to imprint lithography process.

[0192] Another concern with overlay alignment for imprint lithographyprocesses that use UV curable liquid materials may be the visibility ofthe alignment marks. For the overlay placement error measurement, twooverlay marks, one on the template and the other on substrate are used.However, since it is desirable for the template to be transparent to acuring agent, the template overlay marks, in some embodiments, are notopaque lines. Rather, the template overlay marks are topographicalfeatures of the template surface. In some embodiment, the marks are madeof the same material as the template. In addition, UV curable liquidsmay have a refractive index that is similar to the refractive index ofthe template materials (e.g., quartz). Therefore, when the UV curableliquid fills the gap between the template and the substrate, templateoverlay marks may become very difficult to recognize. If the templateoverlay marks are made with an opaque material (e.g., chromium), the UVcurable liquid below the overlay marks may not be properly exposed tothe UV light.

[0193] In an embodiment, overlay marks are used on the template that areseen by the optical imaging system 3800 but are opaque to the curinglight (e.g., UV light). An embodiment of this approach is illustrated inFIG. 31. In FIG. 31, instead of completely opaque lines, overlay marks3102 on the template may be formed of fine polarizing lines 3101. Forexample, suitable fine polarizing lines have a width about ½ to ¼ of thewavelength of activating light used as the curing agent. The line widthof polarizing lines 3101 should be small enough so that activating lightpassing between two lines is diffracted sufficiently to cause curing ofall the liquid below the lines. In such an embodiment, the activatinglight may be polarized according to the polarization of overlay marks3102. Polarizing the activating light provides a relatively uniformexposure to all the template regions including regions having overlaymarks 3102. Light used to locate overlay marks 3102 on the template maybe broadband light or a specific wavelength that may not cure the liquidmaterial. This light need not be polarized. Polarized lines 3101 aresubstantially opaque to the measuring light, thus making the overlaymarks visible using established overlay error measuring tools. Finepolarized overlay marks are fabricated on the template using existingtechniques, such as electron beam lithography.

[0194] In another embodiment, overlay marks are formed of a differentmaterial than the template. For example, a material selected to form thetemplate overlay marks may be substantially opaque to visible light, buttransparent to activating light used as the curing agent (e.g., UVlight). For example, SiOx where X is less than 2 may be used as such amaterial. In particular, structures formed of SiOx where X is about 1.5are substantially opaque to visible light, but transparent to UV curinglight.

[0195] Liquid Dispensing Patterns

[0196] In all embodiments of an imprint lithography process, a liquid isdispensed onto a substrate. While the following description is directedto dispensing liquids on substrate, it should be understood that thesame liquid dispensing techniques are also used when dispensing liquidsonto a template. Liquid dispensing is a carefully controlled process. Ingeneral, liquid dispensing is controlled such that a predeterminedamount of liquid is dispensed in the proper location on the substrate.Additionally, the volume of liquid is also controlled. The combinationof the proper volume of liquid and the proper location of the liquid iscontrolled by using the liquid dispensing systems described herein. Stepand repeat processes, in particular, use a combination of liquid volumecontrol and liquid placement to confine patterning to a specified field.

[0197] A variety of liquid dispensing patterns are used. Patterns may bein the form a continuous lines or patterns of droplets of liquid. Insome embodiments, relative motion between a displacement based liquiddispenser tip and an imprinting member is used to form a pattern withsubstantially continuous lines on a portion of the imprinting member.Balancing rates of dispensing and relative motion is used to control thesize of the cross section of the line and the shape of the line. Duringthe dispensing process, the dispenser tips are fixed near (e.g., on theorder of tens of microns) to the substrate. Two examples of continuouspatterns are depicted in FIGS. 32A and 32B. The pattern depicted inFIGS. 32A and 32B is a sinusoidal pattern; however, other patterns arepossible. As depicted in FIGS. 32A and 32B continuous line pattern maybe drawn using either a single dispenser tip 2401 or multiple dispensertips 2402. Alternate, a pattern of droplets may be used, as depicted inFIG. 32C. In one embodiment, a pattern of droplets that has a centraldroplet that has a greater volume than surrounding droplets is used.When the template contacts the droplets, the liquid spreads to fill thepatterning area of the template as indicated in the FIG. 32C.

[0198] Dispensing rate, V_(d), and relative lateral velocity of animprinting member, v_(s), may be related as follows:

v _(d) =V _(d) /t _(d) (dispensing volume/dispensing period),  (1)

v _(s) =L/t _(d) (line length/dispensing period),  (2)

V _(d) =a L (where, ‘a’ is the cross section area of line pattern),  (3)

[0199] Therefore,

v _(d) =a v _(s).  (4)

[0200] The width of the initial line pattern may normally depend on thetip size of a dispenser. The dispenser tip may be fixed. In anembodiment, a liquid dispensing controller is used to control the volumeof liquid dispensed (V_(d)) and the time taken to dispense the liquid(t_(d)). If V_(d) and t_(d) are fixed, increasing the length of the lineleads to lower height of the cross section of the line patterned.Increasing pattern length may be achieved by increasing the spatialfrequency of the periodic patterns. Lower height of the pattern may leadto a decrease in the amount of liquid to be displaced during imprintprocesses. By using multiple tips connected to the same dispensing line,line patterns with long lengths may be formed faster as compared to thecase of a single dispenser tip. Alternatively a plurality of closelyspaced drops is used to form a line with an accurate volume.

[0201] Separation of Template

[0202] After curing of the liquid is completed, the template isseparated from the cured liquid. Since the template and substrate arealmost perfectly parallel, the assembly of the template, imprintedlayer, and substrate leads to a substantially uniform contact betweenthe template and the cured liquid. Such a system may require a largeseparation force to separate the template from the cured liquid. In thecase of a flexible template or substrate, the separation, in oneembodiment, is performed using a “peeling process.” However, use of aflexible template or substrate may be undesirable for high-resolutionoverlay alignment. In the case of a quartz template and a siliconsubstrate, a peeling process may be difficult to implement. In oneembodiment, a “peel and pull” process is performed to separate thetemplate from an imprinted layer. An embodiment of a peel and pullprocess is illustrated in FIGS. 33A, 33B, and 33C.

[0203]FIG. 33A depicts a template 12 embedded in a cured layer 40 aftercuring. After curing of the substance 40, either the template 12 orsubstrate 20 may be tilted to intentionally induce an angle 3604 betweenthe template 12 and substrate 20, as depicted in FIG. 35B. Apre-calibration stage, either coupled to the template or the substratemay be used to induce a tilt between the template and the cured layer40. The relative lateral motion between the template 12 and substrate 20may be insignificant during the tilting motion if the tilting axis islocated close to the template-substrate interface. Once angle 3604between template 12 and substrate 20 is large enough, template 12 may beseparated from the substrate 20 using only Z-axis motion (i.e., verticalmotion). This peel and pull method may result in desired features 44being left intact on a transfer layer 18 and substrate 20 withoutundesirable shearing.

[0204] Electrostatic Curing Process

[0205] In addition to the above-described embodiments, embodimentsdescribed herein include forming patterned structures by using electricfields. Cured layers formed using electric fields to induce a pattern inthe cured layer may be used for single imprinting or step and repeatprocesses.

[0206]FIG. 34 depicts an embodiment of template 1200 and substrate 1202.Template 1200, in one embodiment, is formed from a material that istransparent to activating light to allow curing of the polymerizablecomposition by exposure to activating light. Forming template 1200 froma transparent material also allows the use of established opticaltechniques to measure the gap between template 1200 and substrate 1202and to measure overlay marks to perform overlay alignment andmagnification correction during formation of the structures. Template1200 is also thermally and mechanically stable to providenano-resolution patterning capability. Template 1200 includes anelectrically conducting material and/or layer 1204 to allow electricfields to be generated at template-substrate interface.

[0207] In one embodiment, a blank of fused silica (e.g., quartz) is usedas the material for base 1206 of template 1200. Indium Tin Oxide (ITO)is deposited onto base 1206. ITO is transparent to visible and UV lightand is a conducting material. ITO may be patterned using highresolutionelectron beam lithography. A low-surface energy coating, as previouslydescribed, may be coated onto the template to improve the releasecharacteristics between the template and the polymerized composition.Substrate 1202 may include standard wafer materials such as Si, GaAs,SiGeC and InP. A UV curable liquid and/or a thermally curable liquid maybe used as polymerizable composition 1208. In an embodiment,polymerizable composition 1208 may be spin coated onto the wafer 1210.In another embodiment, a predetermined volume of polymerizablecomposition 1208 may be dispensed onto the substrate in a predeterminedpattern, as described herein. In some embodiments, transfer layer 1212may be placed between wafer 1210 and polymerizable composition 1208.Transfer layer 1212 material properties and thickness may be chosen toallow for the creation of high-aspect ratio structures from low-aspectratio structures created in the cured liquid material. Connecting ITO toa voltage source 1214 may generate an electric field between template1200 and substrate 1202.

[0208] In FIG. 35 A-D and FIG. 36 A-C, two embodiments of theabove-described process are illustrated. In each embodiment, a desireduniform gap may be maintained between the template and the substrate. Anelectric field of the desired magnitude may be applied resulting in theattraction of polymerizable composition 1208 towards the raised portions1216 of template 1200. In FIG. 35 A-D, the gap and field magnitudes aresuch that polymerizable composition 1208 makes direct contact andadheres to template 1200. A curing agent (e.g., activating light 1218and/or heat) may be used to cure the liquid. Once desired structureshave been formed, template 1200 may be separated from substrate 1202 bymethods described herein.

[0209] In FIG. 36 A-C, the gap and field magnitudes may be chosen suchthat polymerizable composition 1208 achieves a topography that isessentially the same as that of template 1200. This topography may beachieved without making direct contact with the template. A curing agent(e.g. activating light 1218) may be used to cure the liquid. In theembodiment of FIG. 35 A-D and FIG. 36 A-C, a subsequent etch process maybe used to remove the cured material 1220. A further etch may also beused if transfer layer 1212 is present between cured material 1220 andwafer 1210 as shown in FIG. 35 A-D and FIG. 36 A-C.

[0210] In another embodiment, FIG. 37A depicts an electricallyconductive template that includes a continuous layer of electricallyconductive portions 1504 coupled to a non-conductive base 1502. As shownin FIG. 37B the non-conductive portions 1502 of the template areisolated from each other by the conductive portions 1504. The templatemay be used to in a “positive” imprint process as described above.

[0211] In an embodiment, an “adjustable” template may be used to form apattern on a substrate. The term “adjustable” template, in the contextof this embodiment, generally refers to a template that includeselectrically conductive portions that are independently controlled.Controlling a conductive portion of the template refers to turning on,turning off, and/or adjusting an electric field of the conductiveportion. This concept is illustrated in FIG. 38. Template 1700 includeselectrically conductive portions 1702 and non-conductive material 1704.Non-conductive material 1704 insulates conductive portions 1702 fromeach other. Template 1700 is substantially transparent to some or alltypes of activating light. In an embodiment, template 1700 is formedfrom materials that are thermally stable. Conductive portions 1702 maybe formed from, for example, ITO. Non-conductive material 1704 may beformed from, for example, silicon dioxide. Conductive portions 1702 forma pattern complementary to a pattern to be produced on a masking layer.The pattern of conductive portions 1702 is formed in non-conductingmaterial 1704 using methods known to those skilled in the art.Conductive portions 1702 are be electrically connected 1706 to powersource 1708, either independently or together. In an embodiment wherethe conductive portions 1702 are independently connected to power source1708, there may be a control device 1710 to independently adjust theelectric field generated by one or more of conductive portions 1702. Inan embodiment, electrical connectors 1712 run through non-conductivematerial 1704 from another side to connect to conductive portions 1702.In an alternate embodiment, conductive portions 1702 extend throughnon-conductive material 1704 such that electrical connectors 1712 arenot required.

[0212] Such embodiments may create lithographic patterned structuresquickly (in a time of less than about 1 second). The structuresgenerally have sizes of tens of nanometers. In one embodiment, curing apolymerizable composition in the presence of electric fields creates apatterned layer on a substrate. The pattern is created by placing atemplate with specific nanometer-scale topography at a controlleddistance (e.g., within nanometers) from the surface of a thin layer ofthe curable liquid on a substrate. If all or a portion of the desiredstructures are regularly repeating patterns (such as an array of dots),the pattern on the template may be considerably larger than the size ofthe desired repeating structures.

[0213] The replication of the pattern on the template may be achieved byapplying an electric field between the template and the substrate.Because the liquid and air (or vacuum) have different dielectricconstants and the electric field varies locally due to the presence ofthe topography of the template, an electrostatic force may be generatedthat attracts regions of the liquid toward the template. Surface tensionor capillary pressures tend to stabilize the film. At high electricfield strengths, the polymerizable composition may be made to attach tothe template and dewet from the substrate at certain points. However,the attachment of the liquid film will occur provided the ratio ofelectrostatic forces are comparable to the capillary forces, which ismeasured by the dimensionless number Λ. The magnitude of theelectrostatic force is approximately εE²d², where E is the permittivityof vacuum, E is the magnitude of the electric field, and d is thefeature size. The magnitude of the capillary forces is approximately γd,where γ is the liquid-gas surface tension. The ratio of these two forcesis Λ=εE²d/γ. In order to deform the interface and cause it to attach tothe upper surface, the electric field must be such that L isapproximately unity. The precise value depends on the details of thetopography of the plates and the ratio of liquid-gas permittivities andheights, but this number will be O(1). Thus, the electric field isapproximately given by E˜(γ/εd)^(½). This polymerizable composition maybe hardened in place by polymerization of the composition. The templatemay be treated with a low energy self-assembled monolayer film (e.g., afluorinated surfactant) to aid in detachment of the template thepolymerized composition.

[0214] An example of the above approximations is given below. For d=100and γ=30 mJ/m and ε=8.85×10-12 C²/J-m, E=1.8×10⁸ V/m, which correspondsto a potential difference between the plates of modest 18 V if the platespacing is 100 and 180 V is the plate spacing is 1000 nm. Note that thefeature size d˜γ/εE², which means that the size of the feature decreaseswith the square of the electric field. Thus, 50 nm features wouldrequire voltages on the order of 25 or 250 volts for 100 and 1000 nmplate spacings.

[0215] It may be possible to control the electric field, the design ofthe topography of the template and the proximity of the template to theliquid surface so as to create a pattern in the polymerizablecomposition that does not come into contact with the surface of thetemplate. This technique may eliminate the need for mechanicalseparation of the template from the polymerized composition. Thistechnique may also eliminate a potential source of defects in thepattern. In the absence of contact, however, the liquid may not formsharp, high-resolution structures that are as well defined as in thecase of contact. This may be addressed by first creating structures inthe polymerizable composition that are partially defined at a givenelectric field. Subsequently, the gap may be increased between thetemplate and substrate while simultaneously increasing the magnitude ofthe electric field to “draw-out” the liquid to form clearly definedstructures without requiring contact.

[0216] The polymerizable composition may be deposited on top of atransfer layer as previously described. Such a bi-layer process allowslow aspect ratio, high-resolution structures formed using electricalfields to be followed by an etch process to yield high-aspect ratio,high-resolution structures. Such a bi-layer process may also be used toperform a “metal lift-off process” to deposit a metal on the substratesuch that the metal is left behind after lift-off in the trench areas ofthe originally created structures. Using a low viscosity polymerizablecomposition, pattern formation using electric fields may be fast (e.g.,less than about 1 sec.), and the structure may be rapidly cured.Avoiding temperature variations in the substrate and the polymerizablecomposition may also avoid undesirable pattern distortion that makesnano-resolution layer-to-layer alignment impractical. In addition, asmentioned above, it is possible to quickly form a pattern withoutcontact with the template, thus eliminating defects associated withimprint methods that require direct contact.

[0217] In this patent, certain U.S. patents, and U.S. patentapplications have been incorporated by reference. The text of such U.S.patents, and U.S. patent applications is, however, only incorporated byreference to the extent that no conflict exists between such text andthe other statements and drawings set forth herein. In the event of suchconflict, then any such conflicting text in such incorporated byreference U.S. patents, and U.S. patent applications is specifically notincorporated by reference in this patent.

[0218] While this invention has been described with references tovarious illustrative embodiments, the description is not intended to beconstrued in a limiting sense. Various modifications and combinations ofthe illustrative embodiments as well as other embodiments of theinvention, will be apparent to persons skilled in the art upon referenceto the description. It is, therefore, intended that the appended claimsencompass any such modifications or embodiments.

What is claimed is:
 1. A system for forming a pattern on a substratecomprising: a body; a patterned template, wherein the patterned templateis substantially transparent to activating light; a motion stage coupledto the body, wherein the motion stage is configured to support asubstrate, and wherein the motion stage is configured to move thesubstrate along a plane substantially parallel to the patternedtemplate; an imprint head coupled to the body, wherein the imprint headis configured to hold the patterned template proximate to the substrateduring use, wherein the imprint head comprises a fine orientationsystem, wherein the fine orientation system is configured to allowmotion of the patterned template with respect to the substrate toachieve a substantially parallel orientation of the patterned templatewith respect to the substrate; a force detector coupled to the imprinthead, wherein the force detector is configured to determine a resistiveforce applied to the template by the applied liquid when the templatecontacts the applied liquid; a liquid dispenser coupled to the body,wherein the liquid dispenser is configured to dispense an activatinglight curable liquid onto at least a portion of the substrate duringuse; and an activating light source optically coupled to the patternedtemplate, wherein the activating light source is configured to directactivating light through the patterned template during use.
 2. Thesystem of claim 1, wherein the fine orientation system is configured toallow motion of the patterned template to a substantially parallelorientation with respect to the substrate when the template contacts aliquid disposed on the substrate.
 3. The system of claim 1, wherein thefine orientation system comprises one or more passive compliant members.4. The system of claim 1, wherein the fine orientation system comprises:a first flexure member, wherein the first flexure member is configuredto pivot about a first orientation axis during use; a second flexuremember coupled to the first flexure member, wherein the second flexuremember is configured to pivot about a second orientation axis duringuse; and a support coupled to the second flexure member, wherein thesupport is configured to hold the patterned template during use; whereinthe second flexure member is coupled to the first flexure member suchthat the patterned template, when disposed in the support, moves about apivot point intersected by the first and second orientation axis duringuse.
 5. The system of claim 4, wherein the first flexure membercomprises first and second arms, wherein the first arm comprises a firstset of flexure joints which are configured to provide pivotal motion ofthe first flexure member about the first orientation axis, and whereinthe second arm comprises a second set of flexure joints which areconfigured to provide pivotal motion of the first flexure member aboutthe first orientation axis, and wherein the second flexure membercomprises third and fourth arms, wherein the third arm comprises a thirdset of flexure joints which are configured to provide pivotal motion ofthe second flexure member about the second orientation axis, and whereinthe fourth arm comprises a fourth set of flexure joints which areconfigured to provide pivotal motion of the second flexure member aboutthe second orientation axis.
 6. The system of claim 4, wherein the firstflexure member comprises a first opening, the second flexure membercomprises a second opening, and the support comprises a third opening,wherein each of the first, second and third openings are configured toallow activating light to be directed onto the template during use,wherein the first, second and third openings are substantially alignedwhen the first flexure member is coupled to the second flexure member.7. The system of claim 4, further comprising a precalibration stagecoupled to the fine orientation system, wherein the precalibration stageis configured to move the fine orientation system toward and away fromthe substrate during use.
 8. The system of claim 1, further comprising asupport structure coupled to the imprint head and to the motion stage,wherein the support structure comprises a material having a linearthermal expansion coefficient of less than about 20 ppm/° C. at about25° C.
 9. The system of claim 1, further comprising a support structurecoupled to the imprint head and to the motion stage, wherein the supportstructure comprises a material having a linear thermal expansioncoefficient of less than about 10 ppm/° C. at about 25° C.
 10. Thesystem of claim 1, further comprising a support structure coupled to theimprint head and to the motion stage, wherein the support structurecomprises a material having a linear thermal expansion coefficient ofless than about 1 ppm/° C. at about 25° C.
 11. The system of claim 1,wherein the motion stage comprises an air-bearing stage.
 12. The systemof claim 1, further comprising an encoder system coupled to the motionstage, wherein the linear encoder system is configured to determine thedisplacement of the motion stage with respect to a reference point onthe body.
 13. The system of claim 12, wherein the encoder systemcomprises a glass scale linear encoder system.
 14. The system of claim1, further comprising an encoder system coupled to the motion stage,wherein the linear encoder system is configured to determine thedisplacement of the motion stage toward the template with respect to areference point on the body.
 15. The system of claim 1, furthercomprising an enclosure around at least the imprint head and the motionstage, and a temperature control system, wherein the temperature controlsystem is configure to inhibit temperature variations of greater thanabout 1° C. within the enclosure during use.
 16. The system of claim 1,further comprising an enclosure around at least the imprint head and themotion stage, and a temperature control system, wherein the temperaturecontrol system is configure to inhibit temperature variations of greaterthan about 0.1° C. within the enclosure during use.
 17. The system ofclaim 1, wherein at least a portion of the first surface of thepatterned template comprises a surface treatment layer.
 18. The systemof claim 1, wherein the patterned template further comprises a surfacetreatment layer on at least a portion of the first surface, and whereinthe surface treatment layer comprises a reaction product of analkylsilane, a fluoroalkylsilane, or a fluoroalkyltrichlorosilane withwater.
 19. The system of claim 1, wherein the patterned template furthercomprises a surface treatment layer on at least a portion of the firstsurface, and wherein the surface treatment layer comprises a reactionproduct of tridecafluoro- 1,1,2,2-tetrahydrooctyl trichlorosilane withwater.
 20. The system of claim 1, wherein the patterned template furthercomprises a surface treatment layer on at least a portion of the lowersurface, and wherein the surface treatment layer reduces the surfacefree energy of the lower surface measured at 25° C. to less than about40 dynes/cm.
 21. The system of claim 1, wherein at least a portion ofthe template comprises silicon, silicon dioxide, silicon germaniumcarbon, gallium nitride, silicon germanium, sapphire, gallium arsenide,epitaxial silicon, poly-silicon, gate oxide, quartz, indium tin oxide,an oxide of silicon or a combination thereof.
 22. The system of claim 1,wherein the liquid dispenser is coupled to the imprint head.
 23. Thesystem of claim 1, further comprising an air gauge coupled to theimprint head, wherein the air gauge is configured to determine adistance between the substrate and the template.
 24. The system of claim1, further comprising an air gauge coupled to the motion stage, whereinthe air gauge is configured to determine a distance between thesubstrate and the template.
 25. The system of claim 1, wherein theimprint head is configured to move the template toward the substrateduring use.
 26. The system of claim 1, wherein the imprint head isconfigured to move the patterned template toward the substrate duringuse.
 27. The system of claim 1, wherein the motion stage is configuredto move the substrate toward the patterned template during use.
 28. Thesystem of claim 1, wherein the motion stage is positioned below theimprint head.
 29. The system of claim 1, wherein the motion stage ispositioned above the imprint head.
 30. The system of claim 1, whereinthe activating light source is positioned with respect to the body suchthat the activating light source is thermally insulated from the body.31. A system for forming a pattern on a substrate comprising: a body; apatterned template, wherein the patterned template is substantiallytransparent to activating light; a motion stage coupled to the body,wherein the motion stage is configured to support a substrate, andwherein the motion stage is configured to move the substrate along aplane substantially parallel to the patterned template, and wherein themotion stage comprises a fine orientation system, wherein the fineorientation system is configured to allow motion of the substrate withrespect to the patterned template to achieve a substantially parallelorientation of the substrate with respect to the patterned template; animprint head coupled to the body, wherein the imprint head is configuredto hold the patterned template proximate to the substrate during use, aforce detector coupled to the imprint head, wherein the force detectoris configured to determine a resistive force applied to the template bythe applied liquid when the template contacts the applied liquid; aliquid dispenser coupled to the body, wherein the liquid dispenser isconfigured to dispense an activating light curable liquid onto at leasta portion of the substrate during use; and p1 an activating light sourceoptically coupled to the patterned template, wherein the activatinglight source is configured to direct activating light through thepatterned template during use.
 32. The system of claim 31, furthercomprising a support structure coupled to the imprint head and to themotion stage, wherein the support structure comprises a material havinga linear thermal expansion coefficient of less than about 20 ppm/° C. atabout 25° C.
 33. The system of claim 31, further comprising an enclosurearound at least the imprint head and the motion stage, and a temperaturecontrol system, wherein the temperature control system is configure toinhibit temperature variations of greater than about 1° C. within theenclosure during use.
 34. The system of claim 31, wherein at least aportion of the first surface of the patterned template comprises asurface treatment layer.
 35. A system for forming a pattern on asubstrate comprising: a body; a patterned template, wherein thepatterned template is substantially transparent to activating light; animprint head, wherein the imprint head is configured to hold thepatterned template; a motion stage coupled to the body, wherein themotion stage is configured to support the imprint head, and wherein themotion stage is configured to move the imprint head along a planesubstantially parallel to the substrate, wherein the imprint headcomprises a fine orientation system, wherein the fine orientation systemis configured to allow motion of the patterned template with respect tothe substrate to achieve a substantially parallel orientation of thepatterned template with respect to the substrate; a substrate supportcoupled to the body, wherein the substrate support is configured to holdthe substrate proximate to the patterned template during use, a liquiddispenser coupled to the motion stage, wherein the liquid dispenser isconfigured to dispense an activating light curable liquid onto at leasta portion of the substrate during use; and an activating light sourceoptically coupled to the patterned template, wherein the activatinglight source is configured to direct activating light through thepatterned template during use.
 36. The system of claim 35, wherein theliquid dispenser is coupled to the imprint head.
 37. The system of claim35, further comprising a force detector coupled to the imprint head,wherein the force detector is configured to determine a resistive forceapplied to the template by the applied liquid when the template contactsthe applied liquid.
 38. The system of claim 35, further comprising asupport structure coupled to the imprint head and to the motion stage,wherein the support structure comprises a material having a linearthermal expansion coefficient of less than about 20 ppm/° C. at about25° C.
 39. The system of claim 35, further comprising an enclosurearound at least the imprint head and the motion stage, and a temperaturecontrol system, wherein the temperature control system is configure toinhibit temperature variations of greater than about 1° C. within theenclosure during use.
 40. The system of claim 35, wherein at least aportion of the first surface of the patterned template comprises asurface treatment layer.
 41. A system for forming a pattern on asubstrate comprising: a body; a patterned template, wherein thepatterned template is substantially transparent to activating light; animprint head, wherein the imprint head is configured to hold thepatterned template; a motion stage coupled to the body, wherein themotion stage is configured to support the imprint head, and wherein themotion stage is configured to move the imprint head along a planesubstantially parallel to the substrate; a substrate support coupled tothe body, wherein the substrate support is configured to hold thesubstrate proximate to the patterned template during use, and whereinthe substrate support comprises a fine orientation system, wherein thefine orientation system is configured to allow motion of the substratewith respect to the patterned template to achieve a substantiallyparallel orientation of the substrate with respect to the patternedtemplate a liquid dispenser coupled to the motion stage, wherein theliquid dispenser is configured to dispense an activating light curableliquid onto at least a portion of the substrate during use; and anactivating light source optically coupled to the patterned template,wherein the activating light source is configured to direct activatinglight through the patterned template during use.
 42. The system of claim41, further comprising a support structure coupled to the imprint headand to the motion stage, wherein the support structure comprises amaterial having a linear thermal expansion coefficient of less thanabout 20 ppm/° C. at about 25° C.
 43. The system of claim 41, furthercomprising an enclosure around at least the imprint head and the motionstage, and a temperature control system, wherein the temperature controlsystem is configure to inhibit temperature variations of greater thanabout 1° C. within the enclosure during use.
 44. The system of claim 41,wherein at least a portion of the first surface of the patternedtemplate comprises a surface treatment layer.
 45. A system for forming apattern on a substrate comprising: a body; a patterned template, whereinthe patterned template is substantially transparent to activating light,and wherein the patterned template comprises a first surface and aplurality of recesses formed in a patterning area of the templateextending from the first surface toward a second surface of thetemplate, where the recesses define a plurality of features in the firstsurface of the patterned template, and wherein the patterned templatecomprises a border formed about the perimeter of the patterned template,wherein a depth of the border is greater than a depth of the recesses; amotion stage coupled to the body, wherein the motion stage is configuredto support a substrate, and wherein the motion stage is configured tomove the substrate along a plane substantially parallel to the patternedtemplate; an imprint head coupled to the body, wherein the imprint headis configured to hold the patterned template proximate to the substrateduring use, wherein the imprint head comprises a fine orientationsystem, wherein the fine orientation system is configured to allowmotion of the patterned template with respect to the substrate toachieve a substantially parallel orientation of the patterned templatewith respect to the substrate; a force detector coupled to the imprinthead, wherein the force detector is configured to determine a resistiveforce applied to the template by the applied liquid when the templatecontacts the applied liquid; a liquid dispenser coupled to the body,wherein the liquid dispenser is configured to dispense an activatinglight curable liquid onto at least a portion of the substrate duringuse; and an activating light source coupled to the body, wherein theactivating light source is configured to direct activating light throughthe patterned template during use.
 46. The system of claim 45, whereinthe liquid dispenser is configured to dispense a volume of liquid lessthan about 200 nL.
 47. The system of claim 45, wherein the liquiddispenser is configured to dispense a volume of liquid less than about50 nL.
 48. The system of claim 45, wherein the liquid dispenser isconfigured to dispense a volume of liquid less than about 5 nL.
 49. Thesystem of claim 45, wherein at least a portion of the features of thepatterned template have a feature size of less than about 200 nm. 50.The system of claim 45, further comprising a support structure coupledto the imprint head and to the motion stage, wherein the supportstructure comprises a material having a linear thermal expansioncoefficient of less than about 20 ppm/° C. at about 25° C.
 51. Thesystem of claim 45, further comprising an enclosure around at least theimprint head and the motion stage, and a temperature control system,wherein the temperature control system is configure to inhibittemperature variations of greater than about 1° C. within the enclosureduring use.
 52. The system of claim 45, wherein at least a portion ofthe first surface of the patterned template comprises a surfacetreatment layer.
 53. A system for forming a pattern on a substratecomprising: a body; a patterned template, wherein the patterned templateis substantially transparent to activating light, and wherein thepatterned template comprises a first surface and a plurality of recessesformed in a patterning area of the template extending from the firstsurface toward a second surface of the template, where the recessesdefine a plurality of features in the first surface of the patternedtemplate, and wherein the patterned template comprises a border formedabout the perimeter of the patterning area, wherein a depth of theborder is greater than a depth of the recesses; a motion stage coupledto the body, wherein the motion stage is configured to support asubstrate, and wherein the motion stage is configured to move thesubstrate along a plane substantially parallel to the patternedtemplate, and wherein the motion stage comprises a fine orientationsystem, wherein the fine orientation system is configured to allowmotion of the substrate with respect to the patterned template toachieve a substantially parallel orientation of the substrate withrespect to the patterned template; an imprint head coupled to the body,wherein the imprint head is configured to hold the patterned templateproximate to the substrate during use, a force detector coupled to themotion stage, wherein the force detector is configured to determine aresistive force applied to the substrate by the applied liquid when thetemplate contacts the applied liquid; a liquid dispenser coupled to thebody, wherein the liquid dispenser is configured to dispense anactivating light curable liquid onto at least a portion of the substrateduring use; and an activating light source optically coupled to thepatterned template, wherein the activating light source is configured todirect activating light through the patterned template during use. 54.The system of claim 53, further comprising a support structure coupledto the imprint head and to the motion stage, wherein the supportstructure comprises a material having a linear thermal expansioncoefficient of less than about 20 ppm/° C. at about 25° C.
 55. Thesystem of claim 53, further comprising an enclosure around at least theimprint head and the motion stage, and a temperature control system,wherein the temperature control system is configure to inhibittemperature variations of greater than about 1° C. within the enclosureduring use.
 56. The system of claim 53, wherein at least a portion ofthe first surface of the patterned template comprises a surfacetreatment layer.
 57. A system for forming a pattern on a substratecomprising: a body; a patterned template, wherein the patterned templateis substantially transparent to activating light, and wherein thepatterned template comprises a first surface and a plurality of recessesformed in a patterning area of the template extending from the firstsurface toward a second surface of the template, where the recessesdefine a plurality of features in the first surface of the patternedtemplate, and wherein the patterned template comprises a border formedabout the perimeter of the patterning area, wherein a depth of theborder is greater than a depth of the recesses; an imprint head, whereinthe imprint head is configured to hold the patterned template; a motionstage coupled to the body, wherein the motion stage is configured tosupport the imprint head, and wherein the motion stage is configured tomove the imprint head along a plane substantially parallel to thesubstrate, wherein the imprint head comprises a fine orientation system,wherein the fine orientation system is configured to allow motion of thepatterned template with respect to the substrate to achieve asubstantially parallel orientation of the patterned template withrespect to the substrate; a substrate support coupled to the body,wherein the substrate support is configured to hold the substrateproximate to the patterned template during use, a liquid dispensercoupled to the motion stage, wherein the liquid dispenser is configuredto dispense an activating light curable liquid onto at least a portionof the substrate during use; and an activating light source opticallycoupled to the patterned template, wherein the activating light sourceis configured to direct activating light through the patterned templateduring use.
 58. The system of claim 57, further comprising a supportstructure coupled to the imprint head and to the motion stage, whereinthe support structure comprises a material having a linear thermalexpansion coefficient of less than about 20 ppm/° C. at about 25° C. 59.The system of claim 57, further comprising an enclosure around at leastthe imprint head and the motion stage, and a temperature control system,wherein the temperature control system is configure to inhibittemperature variations of greater than about I° C. within the enclosureduring use.
 60. The system of claim 57, wherein at least a portion ofthe first surface of the patterned template comprises a surfacetreatment layer.
 61. A system for forming a pattern on a substratecomprising: a body; a patterned template, wherein the patterned templateis substantially transparent to activating light, and wherein thepatterned template comprises a first surface and a plurality of recessesformed in a patterning area of the template extending from the firstsurface toward a second surface of the template, where the recessesdefine a plurality of features in the first surface of the patternedtemplate, and wherein the patterned template comprises a border formedabout the perimeter of the patterning area, wherein a depth of theborder is greater than a depth of the recesses; an imprint head, whereinthe imprint head is configured to hold the patterned template; a motionstage coupled to the body, wherein the motion stage is configured tosupport the imprint head, and wherein the motion stage is configured tomove the imprint head along a plane substantially parallel to thesubstrate; a substrate support coupled to the body, wherein thesubstrate support is configured to hold the substrate proximate to thepatterned template during use, and wherein the substrate supportcomprises a fine orientation system, wherein the fine orientation systemis configured to allow motion of the substrate with respect to thepatterned template to achieve a substantially parallel orientation ofthe substrate with respect to the patterned template a liquid dispensercoupled to the motion stage, wherein the liquid dispenser is configuredto dispense an activating light curable liquid onto at least a portionof the substrate during use; and an activating light source opticallycoupled to the patterned template, wherein the activating light sourceis configured to direct activating light through the patterned templateduring use.
 62. The system of claim 61, further comprising a supportstructure coupled to the imprint head and to the motion stage, whereinthe support structure comprises a material having a linear thermalexpansion coefficient of less than about 20 ppm° C. at about 25° C. 63.The system of claim 61, further comprising an enclosure around at leastthe imprint head and the motion stage, and a temperature control system,wherein the temperature control system is configure to inhibittemperature variations of greater than about 1° C. within the enclosureduring use.
 64. The system of claim 61, wherein at least a portion ofthe first surface of the patterned template comprises a surfacetreatment layer.
 65. A system for forming a pattern on a substratecomprising: a body; a patterned template, wherein the patterned templateis substantially transparent to activating light; a motion stage coupledto the body, wherein the motion stage is configured to support asubstrate, and wherein the motion stage is configured to move thesubstrate along a plane substantially parallel to the patternedtemplate, wherein the motion stage comprises: a substrate chuckconfigured to support the substrate; and a substrate tilt module coupledto the substrate chuck, wherein the substrate tilt module is configuredto alter the tilt of the substrate when the substrate is coupled to thesubstrate chuck, and wherein the substrate chuck and substrate tiltmodule have a stiffness sufficient to inhibit tilt of the substrate whenthe template applies a force to a liquid disposed on the substrate; animprint head coupled to the body, wherein the imprint head is configuredto hold the patterned template proximate to the substrate during use,wherein the imprint head comprises a fine orientation system, whereinthe fine orientation system is configured to allow motion of thepatterned template with respect to the substrate to achieve asubstantially parallel orientation of the patterned template withrespect to the substrate; a force detector coupled to the imprint head,wherein the force detector is configured to determinne a resistive forceapplied to the template by the applied liquid when the template contactsthe applied liquid; a liquid dispenser coupled to the body, wherein theliquid dispenser is configured to dispense an activating light curableliquid onto at least a portion of the substrate during use; and anactivating light source optically coupled to the patterned template,wherein the activating light source is configured to direct activatinglight through the patterned template during use.
 66. The system of claim65 wherein the substrate tilt module has a stiffness sufficient toinhibit tilt of the substrate when the template applies a force ofbetween about 1 lb. to about 10 lbs. to a liquid disposed on thesubstrate.
 67. The system of claim 65 wherein the substrate tilt modulehas a stiffness sufficient to allow inhibit tilt of the substrate whenthe template applies a force to a liquid disposed on the substrate,wherein the tilt of the substrate is less than about 5 micro radianswhen the template applies a force of between about 1 lb. to about 10 lb.68. The system of claim 65, further comprising an air gauge coupled tothe imprint head, where the air gauge is configured to determine thetilt of the substrate when the substrate is coupled to the motion stage.69. The system of claim 65, further comprising a support structurecoupled to the imprint head and to the motion stage, wherein the supportstructure comprises a material having a linear thermal expansioncoefficient of less than about 20 ppm/° C. at about 25° C.
 70. Thesystem of claim 65, further comprising an enclosure around at least theimprint head and the motion stage, and a temperature control system,wherein the temperature control system is configure to inhibittemperature variations of greater than about 1° C. within the enclosureduring use.
 71. The system of claim 65, wherein at least a portion ofthe first surface of the patterned template comprises a surfacetreatment layer.
 72. A system for forming a pattern on a substratecomprising: a body; a patterned template, wherein the patterned templateis substantially transparent to activating light; a motion stage coupledto the body, wherein the motion stage is configured to support asubstrate, and wherein the motion stage is configured to move thesubstrate along a plane substantially parallel to the patternedtemplate, and wherein the motion stage comprises: a substrate chuckconfigured to support the substrate; and a substrate tilt module coupledto the substrate chuck, wherein the substrate tilt module is configuredto alter the tilt of the substrate when the substrate is coupled to thesubstrate chuck, and wherein the substrate tilt module is configured toallow motion of the substrate with respect to the template to achieve asubstantially parallel orientation of the substrate with respect to thepatterned template, and wherein the substrate chuck and substrate tiltmodule have a stiffness sufficient to inhibit tilt of the substrate whenthe template applies a force to a liquid disposed on the substrate; animprint head coupled to the body, wherein the imprint head is configuredto hold the patterned template proximate to the substrate during use; aforce detector coupled to the imprint head, wherein the force detectoris configured to determine a resistive force applied to the template bythe applied liquid when the template contacts the applied liquid; aliquid dispenser coupled to the body, wherein the liquid dispenser isconfigured to dispense an activating light curable liquid onto at leasta portion of the substrate during use; and an activating light sourceoptically coupled to the patterned template, wherein the activatinglight source is configured to direct activating light through thepatterned template during use.
 73. The system of claim 72, furthercomprising a support structure coupled to the imprint head and to themotion stage, wherein the support structure comprises a material havinga linear thermal expansion coefficient of less than about 20 ppm/° C. atabout 25° C.
 74. The system of claim 72, further comprising an enclosurearound at least the imprint head and the motion stage, and a temperaturecontrol system, wherein the temperature control system is configure toinhibit temperature variations of greater than about 1° C. within theenclosure during use.
 75. The system of claim 72, wherein at least aportion of the first surface of the patterned template comprises asurface treatment layer.
 76. A system for forming a pattern on asubstrate comprising: a body; a patterned template, wherein thepatterned template is substantially transparent to activating light; animprint head, wherein the imprint head is configured to hold thepatterned template; a motion stage coupled to the body, wherein themotion stage is configured to support the imprint head, and wherein themotion stage is configured to move the imprint head along a planesubstantially parallel to the substrate, wherein the imprint headcomprises a fine orientation system, wherein the fine orientation systemis configured to allow motion of the patterned template with respect tothe substrate to achieve a substantially parallel orientation of thepatterned template with respect to the substrate; a substrate supportcoupled to the body, wherein the substrate support is configured to holdthe substrate proximate to the patterned template during use, and asubstrate chuck configured to support the substrate; and wherein thesubstrate support comprises: a substrate chuck, and a substrate tiltmodule coupled to the substrate chuck, wherein the substrate tilt moduleis configured to alter the tilt of the substrate when the substrate iscoupled to the substrate chuck, and wherein the substrate chuck andsubstrate tilt module have a stiffness sufficient to inhibit tilt of thesubstrate when the template applies a force to a liquid disposed on thesubstrate; a liquid dispenser coupled to the motion stage, wherein theliquid dispenser is configured to dispense an activating light curableliquid onto at least a portion of the substrate during use; and anactivating light source optically coupled to the patterned template,wherein the activating light source is configured to direct activatinglight through the patterned template during use.
 77. The system of claim76, further comprising a support structure coupled to the imprint headand to the motion stage, wherein the support structure comprises amaterial having a linear thermal expansion coefficient of less thanabout 20 ppm/ ° C. at about 25° C.
 78. The system of claim 76, furthercomprising an enclosure around at least the imprint head and the motionstage, and a temperature control system, wherein the temperature controlsystem is configure to inhibit temperature variations of greater thanabout 1° C. within the enclosure during use.
 79. The system of claim 76,wherein at least a portion of the first surface of the patternedtemplate comprises a surface treatment layer.
 80. A system for forming apattern on a substrate comprising: a body; a patterned template, whereinthe patterned template is substantially transparent to activating light;an imprint head, wherein the imprint head is configured to hold thepatterned template; a motion stage coupled to the body, wherein themotion stage is configured to support the imprint head, and wherein themotion stage is configured to move the imprint head along a planesubstantially parallel to the substrate; a substrate support coupled tothe body, wherein the substrate support is configured to hold thesubstrate proximate to the patterned template during use, and asubstrate chuck configured to support the substrate; and wherein thesubstrate support comprises: a substrate chuck, and a substrate tiltmodule coupled to the substrate chuck, wherein the substrate tilt moduleis configured to alter the tilt of the substrate when the substrate iscoupled to the substrate chuck, and wherein the substrate tilt module isconfigured to allow motion of the substrate with respect to the templateto achieve a substantially parallel orientation of the substrate withrespect to the patterned template, and wherein the substrate chuck andsubstrate tilt module have a stiffness sufficient to inhibit tilt of thesubstrate when the template applies a force to a liquid disposed on thesubstrate; a liquid dispenser coupled to the motion stage, wherein theliquid dispenser is configured to dispense an activating light curableliquid onto at least a portion of the substrate during use; and anactivating light source optically coupled to the patterned template,wherein the activating light source is configured to direct activatinglight through the patterned template during use.
 81. The system of claim80, further comprising a support structure coupled to the imprint headand to the motion stage, wherein the support structure comprises amaterial having a linear thermal expansion coefficient of less thanabout 20 ppm/° C. at about 25° C.
 82. The system of claim 80, furthercomprising an enclosure around at least the imprint head and the motionstage, and a temperature control system, wherein the temperature controlsystem is configure to inhibit temperature variations of greater thanabout 1° C. within the enclosure during use.
 83. The system of claim 80,wherein at least a portion of the first surface of the patternedtemplate comprises a surface treatment layer.